ucb1x00: include linux/semaphore.h

This fixes the following error:

  CC      drivers/mfd/ucb1x00-core.o
  drivers/mfd/ucb1x00-core.c: In function 'ucb1x00_adc_enable':
  drivers/mfd/ucb1x00-core.c:138: error: implicit declaration of function 'down'
  drivers/mfd/ucb1x00-core.c: In function 'ucb1x00_adc_disable':
  drivers/mfd/ucb1x00-core.c:196: error: implicit declaration of function 'up'
  drivers/mfd/ucb1x00-core.c: In function 'ucb1x00_probe':
  drivers/mfd/ucb1x00-core.c:500: error: implicit declaration of function 'sema_init'
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
LKML-Reference: <1249677761-19470-1-git-send-email-u.kleine-koenig@pengutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/mfd/ucb1x00-core.c

@@ -24,6 +24,7 @@
 #include <linux/interrupt.h>
 #include <linux/device.h>
 #include <linux/mutex.h>
+#include <linux/semaphore.h>
 
 #include <mach/dma.h>
 #include <mach/hardware.h>