drm/radeon: remove duplicates check

Completely unnecessary since the ww_mutex used to reserve a buffer
can detect double reservations from the same thread anyway.

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --cc drivers/gpu/drm/radeon/r600_cs.c
Simple merge

diff --cc drivers/gpu/drm/radeon/radeon.h
Simple merge

diff --cc drivers/gpu/drm/radeon/radeon_cs.c
Simple merge

diff --cc drivers/gpu/drm/radeon/radeon_object.c
Simple merge

diff --cc drivers/gpu/drm/radeon/radeon_uvd.c
Simple merge

diff --cc drivers/gpu/drm/radeon/radeon_vce.c
Simple merge