Fix build errors by including linux/semaphore.h:

drivers/staging/cxt1e1/pmcc4_private.h:144: error: field 'sr_sem_busy' has incomplete type
drivers/staging/cxt1e1/pmcc4_private.h:146: error: field 'sr_sem_wait' has incomplete type
drivers/staging/cxt1e1/pmcc4_private.h:189: error: field 'sem_wdbusy' has incomplete type
drivers/staging/cxt1e1/musycc.c:617: error: implicit declaration of function 'down'
drivers/staging/cxt1e1/musycc.c:641: error: implicit declaration of function 'up'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>