drm/amdgpu: complete gfxoff allow signal during suspend without delay

drm/amdgpu: complete gfxoff allow signal during suspend without delay

commit 602e024cb6ff297870a6bf1a2c486a50c0f9f46d upstream.

change guarantees that gfxoff is allowed before moving further in
s2idle sequence to add more reliablity about gfxoff in amdgpu IP's
suspend flow

Signed-off-by: Harsh Jain <harsh.jain@amd.com>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: "Limonciello, Mario" <Mario.Limonciello@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>