V4L/DVB: using vmalloc requires include of linux/vmalloc.h

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/cx18/cx18-alsa-pcm.c

@@ -25,6 +25,7 @@
 
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/vmalloc.h>
 
 #include <media/v4l2-device.h>