drm/i915: Pass atomic state to backlight enable/disable/set callbacks.

drm/i915: Pass atomic state to backlight enable/disable/set callbacks.

Pass crtc_state to the enable callback, and connector_state to all callbacks.
This will eliminate the need to guess for the correct pipe in these
callbacks.

The crtc state is required for pch_enable_backlight to obtain the correct
cpu_transcoder.

intel_dp_aux_backlight's setup function is called before hw readout, so
crtc_state and connector_state->best_encoder are NULL in the enable()
and set() callbacks.

This fixes the following series of warns from intel_get_pipe_from_connector:
[  219.968428] ------------[ cut here ]------------
[  219.968481] WARNING: CPU: 3 PID: 2457 at
drivers/gpu/drm/i915/intel_display.c:13881
intel_get_pipe_from_connector+0x62/0x90 [i915]
[  219.968483]
WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex))
[  219.968485] Modules linked in: nls_iso8859_1 snd_hda_codec_hdmi
snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_codec
snd_hda_core snd_hwdep snd_pcm intel_rapl x86_pkg_temp_thermal coretemp
kvm_intel snd_seq_midi snd_seq_midi_event kvm snd_rawmidi irqbypass
crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc snd_seq
snd_seq_device serio_raw snd_timer aesni_intel aes_x86_64 crypto_simd
glue_helper cryptd lpc_ich snd mei_me shpchp soundcore mei rfkill_gpio
mac_hid intel_pmc_ipc parport_pc ppdev lp parport ip_tables x_tables
autofs4 hid_generic usbhid igb ahci i915 xhci_pci dca xhci_hcd ptp
sdhci_pci sdhci libahci pps_core i2c_hid hid video
[  219.968573] CPU: 3 PID: 2457 Comm: kworker/u8:3 Tainted: G        W
4.10.0-tip-201703010159+ #2
[  219.968575] Hardware name: Intel Corp. Broxton P/NOTEBOOK, BIOS
APLKRVPA.X64.0144.B10.1606270006 06/27/2016
[  219.968627] Workqueue: events_unbound intel_atomic_commit_work [i915]
[  219.968629] Call Trace:
[  219.968640]  dump_stack+0x63/0x87
[  219.968646]  __warn+0xd1/0xf0
[  219.968651]  warn_slowpath_fmt+0x4f/0x60
[  219.968657]  ? drm_printk+0x97/0xa0
[  219.968708]  intel_get_pipe_from_connector+0x62/0x90 [i915]
[  219.968756]  intel_panel_enable_backlight+0x19/0xf0 [i915]
[  219.968804]  intel_edp_backlight_on.part.22+0x33/0x40 [i915]
[  219.968852]  intel_edp_backlight_on+0x18/0x20 [i915]
[  219.968900]  intel_enable_ddi+0x94/0xc0 [i915]
[  219.968950]  intel_encoders_enable.isra.93+0x77/0x90 [i915]
[  219.969000]  haswell_crtc_enable+0x310/0x7f0 [i915]
[  219.969051]  intel_update_crtc+0x58/0x100 [i915]
[  219.969101]  skl_update_crtcs+0x218/0x240 [i915]
[  219.969153]  intel_atomic_commit_tail+0x350/0x1000 [i915]
[  219.969159]  ? vtime_account_idle+0xe/0x50
[  219.969164]  ? finish_task_switch+0x107/0x250
[  219.969214]  intel_atomic_commit_work+0x12/0x20 [i915]
[  219.969219]  process_one_work+0x153/0x3f0
[  219.969223]  worker_thread+0x12b/0x4b0
[  219.969227]  kthread+0x101/0x140
[  219.969230]  ? rescuer_thread+0x340/0x340
[  219.969233]  ? kthread_park+0x90/0x90
[  219.969237]  ? do_syscall_64+0x6e/0x180
[  219.969243]  ret_from_fork+0x2c/0x40
[  219.969246] ---[ end trace 0a8fa19387b9ad6d ]---

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100022
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170612102115.23665-4-maarten.lankhorst@linux.intel.com
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>