drm/amdgpu: fix a warning in amdgpu_ras.c (v2)

drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c: In function ‘amdgpu_ras_fs_init’:
drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c:1284:2: warning: ignoring return value of ‘sysfs_create_group’, declared with attribute warn_unused_result [-Wunused-result]
 1284 |  sysfs_create_group(&adev->dev->kobj, &group);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

v2: just print an error for sysfs group creation failure

Acked-by: Nirmoy Das <nirmoy.das@amd.com>
Reviewed-by: Luben Tuikov <luben.tuikov@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>