staging: udlfb: Add vmalloc.h include

Required for vmalloc_32 and vfree declarations on non-x86 platforms.
Signed-off-by: NAmit Kucheria <amit.kucheria@canonical.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/udlfb/udlfb.c

@@ -21,6 +21,7 @@
 #include <linux/mm.h>
 #include <linux/fb.h>
 #include <linux/mutex.h>
+#include <linux/vmalloc.h>
 
 #include "udlfb.h"