drm/amdgpu/mmhub2.0: add bounds checking for cid

drm/amdgpu/mmhub2.0: add bounds checking for cid

commit 0b26edac4ac5535df1f63e6e8ab44c24fe1acad7 upstream.

The value should never exceed the array size as those
are the only values the hardware is expected to return,
but add checks anyway.

Reviewed-by: Benjamin Cheng <benjamin.cheng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit e064cef4b53552602bb6ac90399c18f662f3cacd)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>