[WATCHDOG] ar7_wdt: fix path to ar7-specific headers

AR7 is currently being resubmitted for mainline inclusion
and we changed the path to the ar7-specific headers
from ar7 to mach-ar7 to reflect the other MIPS-based
boards header hierarchy. This patch will avoid any future
compilation failure due to missing headers.
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/ar7_wdt.c

@@ -37,7 +37,7 @@
 #include <linux/uaccess.h>
 
 #include <asm/addrspace.h>
-#include <asm/ar7/ar7.h>
+#include <asm/mach-ar7/ar7.h>
 
 #define DRVNAME "ar7_wdt"
 #define LONGNAME "TI AR7 Watchdog Timer"