drm/amdgpu: Fix inconsistent indenting

Eliminate the follow smatch warning:

drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c:449
sdma_v5_0_ring_emit_mem_sync() warn: inconsistent indenting.

Reviewed-by: Christian König <christian.koenig@amd.com>
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>