drm/amdgpu: fix invalid use of change_bit

We only need to clear the bit in a 32bit integer.

This fixes a crah on ARM64 and PPC64LE caused by
"drm/amdgpu: update the vm invalidation engine layout V2"

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>