drm/i915: Fix IPS disable in intel_plane_disable_noatomic()

drm/i915: Fix IPS disable in intel_plane_disable_noatomic()

IPS must be disabled prior to disabling the last plane (excluding
the cursor). Make the code do that instead of assuming the primary
plane would be the last one. This is probably 100% theoretical
as the BIOS should never light up the other planes anyway. But
no harm in making the code totally consistent.

Also let's update the ips_enabled flag in the crtc state afterwards
so that the first atomic commit has accurate information about
the state of IPS.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220209113526.7595-6-ville.syrjala@linux.intel.com
Acked-by: Jani Nikula <jani.nikula@intel.com>