TQM5200S: fix commands for STK52xx base board because of missing SM501 grafic controller

Some commands for the STK52xx base board try to access the SM501 grafic
controller. But the TQM5200S has no grafic controller (only the TQM5200
and the TQM5200B have). This patch deactivates the commands accessing
the SM501 for the TQM5200S.

Signed-off-by: Martin Krause <martin.krause@tqs.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>