drm/amdgpu: suppress the compile warning about 64 bit type

Suppress the compile warning below:
drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c:1292
gfx_v11_0_rlc_backdoor_autoload_copy_ucode() warn: should '1 << id' be a 64 bit type?

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Guchun Chen <guchun.chen@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>