MN10300: Fix typo in header guard

Fix a typo in the header guard of asm/ipc.h.
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-mn10300/ipcbuf.h

-#ifndef _ASM_IPCBUF_H_
+#ifndef _ASM_IPCBUF_H
 #define _ASM_IPCBUF_H
 
 /*