drm/i915/dp: Reset frl trained flag before restarting FRL training

drm/i915/dp: Reset frl trained flag before restarting FRL training

[ Upstream commit 63720a561b3c98199adf0c73e152807f15cc3b7f ]

For cases where DP has HDMI2.1 sink and FRL Link issues are detected,
reset the flag to state FRL trained status before restarting FRL
training.

Fixes: 9488a030ac91 ("drm/i915: Add support for enabling link status and recovery")
Cc: Swati Sharma <swati2.sharma@intel.com>
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Cc: Uma Shankar <uma.shankar@intel.com> (v2)
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221011063447.904649-2-ankit.k.nautiyal@intel.com
(cherry picked from commit 47e1a59e60c688c5f95b67277202f05b7e84c189)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>