staging: udlfb: Add vmalloc.h include

Required for vmalloc_32 and vfree declarations on non-x86 platforms.

Signed-off-by: Amit Kucheria <amit.kucheria@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/udlfb/udlfb.c b/drivers/staging/udlfb/udlfb.c
index 0ab9d15..f5416af 100644
--- a/drivers/staging/udlfb/udlfb.c
+++ b/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"