drm/i915/psr: Handle PSR errors

drm/i915/psr: Handle PSR errors

Sink will interrupt source when it have any PSR error.
DP_PSR_VSC_SDP_UNCORRECTABLE_ERROR is a PSR2 but already
handling it here.
The only missing error to be handled is DP_PSR_LINK_CRC_ERROR that
will be taken in care in a futher patch.

v6:
not handling DP_PSR_LINK_CRC_ERROR here

v5:
handling all PSR errors here, so the commit message and
comment have changed

v3:
disabling PSR instead of exiting on error

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180626201644.21932-3-jose.souza@intel.com