arm: fix implicit module.h users by adding it to arch/arm as required.

These files will fail to compile if we dont clean them up in advance
and have them include the appropriate headers they need.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

arch/arm/plat-omap/mailbox.c

@@ -29,6 +29,7 @@
 #include <linux/kfifo.h>
 #include <linux/err.h>
 #include <linux/notifier.h>
+#include <linux/module.h>
 
 #include <plat/mailbox.h>