For PSR2 there is no register to tell HW to keep main link enabled
while PSR2 is active, so don't configure sink DPCD with a
misleading value.

v2: Moving the set of DP_PSR_CRC_VERIFICATION to the else block
of 'if (dev_priv->psr.psr2_enabled)' to another patch. (Rodrigo)

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
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>
Link: https://patchwork.freedesktop.org/patch/msgid/20181204003403.23361-2-jose.souza@intel.com