V4L/DVB (5809): Use mutex instead of semaphore in Philips webcam driver

The Philips webcam driver uses a semaphore as mutex. Use the mutex API
instead of the (binary) semaphore.
--

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/video/pwc/pwc.h b/drivers/media/video/pwc/pwc.h
index acbb931..910a04f 100644
--- a/drivers/media/video/pwc/pwc.h
+++ b/drivers/media/video/pwc/pwc.h
@@ -31,7 +31,7 @@
 #include <linux/wait.h>
 #include <linux/smp_lock.h>
 #include <linux/version.h>
-#include <asm/semaphore.h>
+#include <linux/mutex.h>
 #include <asm/errno.h>
 #include <linux/videodev.h>
 #include <media/v4l2-common.h>
@@ -244,7 +244,7 @@
    int image_read_pos;			/* In case we read data in pieces, keep track of were we are in the imagebuffer */
    int image_used[MAX_IMAGES];		/* For MCAPTURE and SYNC */
 
-   struct semaphore modlock;		/* to prevent races in video_open(), etc */
+   struct mutex modlock;		/* to prevent races in video_open(), etc */
    spinlock_t ptrlock;			/* for manipulating the buffer pointers */
 
    /*** motorized pan/tilt feature */