drm/amdgpu/userq: call dma_resv_wait_timeout without test for signalled

drm/amdgpu/userq: call dma_resv_wait_timeout without test for signalled

In function amdgpu_userq_gem_va_unmap_validate call
dma_resv_wait_timeout directly. Also since we are waiting
forever we should not be having any return value and hence
no handling needed.

Suggested-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>