UBI: use vmalloc for large buffers

UBI allocates temporary buffers of PEB size, which may be 256KiB.
Use vmalloc instead of kmalloc for such big temporary buffers.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

drivers/mtd/ubi/ubi.h

@@ -35,6 +35,7 @@
 #include <linux/cdev.h>
 #include <linux/device.h>
 #include <linux/string.h>
+#include <linux/vmalloc.h>
 #include <linux/mtd/mtd.h>
 
 #include <mtd/ubi-header.h>