staging: most: Remove unnecessary usage of BUG_ON().

There is no need for the calls to BUG_ON() in this driver, which are
used to check if mbo or mbo->context are NULL; mbo is never NULL, and
if mbo->context is NULL it would have already been dereferenced and
oopsed before reaching the BUG_ON().

Signed-off-by: Quytelda Kahja <quytelda@tamalin.org>
Acked-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>