When looking up the connector type make sure the index
is valid.  Avoids a later crash if we read past the end
of the array.

Workaround for bug:
https://bugs.freedesktop.org/show_bug.cgi?id=97460Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org