drm/amd/amdgpu:  Fix debugfs reg read/write address width

The MMIO space is wider now so we mask the lower 22 bits
instead of 18.

Signed-off-by: Tom St Denis <tom.stdenis@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
1 file changed