drm:amd:amdgpu: Fix missing bo unlock in failure path

smatch warning - inconsistent handling of buffer object reserve
and unreserve.
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Sukrut Bellary <sukrut.bellary@linux.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c

@@ -4686,8 +4686,10 @@ static int gfx_v8_0_kiq_resume(struct amdgpu_device *adev)
 		return r;
 
 	r = amdgpu_bo_kmap(ring->mqd_obj, &ring->mqd_ptr);
-	if (unlikely(r != 0))
+	if (unlikely(r != 0)) {
+		amdgpu_bo_unreserve(ring->mqd_obj);
 		return r;
+	}
 
 	gfx_v8_0_kiq_init_queue(ring);
 	amdgpu_bo_kunmap(ring->mqd_obj);