drm/i915/edp: Add a T12 panel delay quirk to fix DP AUX CH timeouts

This patch fixes the DP AUX CH timeouts observed during CI IGT
tests thus fixing the CI failures. This is done by adding a
quirk for a particular PCI device that requires the panel power
cycle delay (T12) to be set to 800ms which is 300msecs more than
the minimum value specified in the eDP spec. So a quirk is
implemented for that specific PCI device.

v4:
* Add Bugzilla links for FDO bugs in the commit message (Ville, Jani)
v3:
* Change some comments, specify the delay as 800 * 10 (Ville)
v2:
* Change the function and variable names to from PPS_T12_
to _T12 since it is a T12 delay (Clint)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101144
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101154
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101167
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101515
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Clinton Taylor <clinton.a.taylor@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Clinton Taylor <clinton.a.taylor@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1498840428-23176-1-git-send-email-manasi.d.navare@intel.com
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>