drm/i915: Ignore "digital output" and "not HDMI output" bits for eDP detection

drm/i915: Ignore "digital output" and "not HDMI output" bits for eDP detection

Ignore DEVICE_TYPE_NOT_HDMI_OUTPUT and DEVICE_TYPE_DIGITAL_OUTPUT when
trying to determine the presence of eDP based on the VBT child device
type. Apparently a significant portion of VLV systems have these bits
set incorrectly, and so we currently fail to detect eDP on said systems.

This is based on an earlier patch [1] from Andreas Lampersperger.
Instead of ignoring the bits just on VLV as was done in the orignal
patch, we now ignore them for all platforms. We should still have
enough bits in there to avoid false positives (unless the VBT is totally
bonkers).

Quoting the orignal patch:
> When the i915.ko identify an eDP output on a valleyview
> board, it should be more slackly. The reason for that is,
> that BIOS DATA TABLES generated with intel BMP (Binary
> Modification Program) do not set bits for NOT_HDMI or
> DIGITAL_OUTPUT on the device type. Due to Adolfo
> Sanchez from Intel EMGD, this is not possible.
> To solve this problem and enable i915.ko on embedded
> vlv boards with eDP, we ignore this two bits.

[1] http://lists.freedesktop.org/archives/intel-gfx/2015-June/069416.html

Cc: Andreas Lampersperger <lampersperger.andreas@heidenhain.de>
Cc: "Sanchez, AdolfoX" <adolfox.sanchez@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>