staging: cxt1e1: fix semaphore build breakage

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>

drivers/staging/cxt1e1/pmcc4_private.h

@@ -20,6 +20,7 @@
 
 #include <linux/kernel.h>
 #include <linux/sched.h>
+#include <linux/semaphore.h>
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>    /* support for tasklets */
 #include <linux/timer.h>        /* support for timer */