drm/amd/display: disable FBC on underlay pipe

FBC is not applicable for the underlay pipe,
hence disallow enabling and disabling of the same.

This also fixes the BUG hit of calling sleep in
atomic context.

Signed-off-by: Shirish S <shirish.s@amd.com>
Reviewed-by: Roman Li <Roman.Li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Shirish S 2018-04-25 14:42:28 +05:30 • committed by Alex Deucher
commit 87ac8fb08b