bug.h: add include of it to various implicit C users

With bug.h currently living right in linux/kernel.h there
are files that use BUG_ON and friends but are not including
the header explicitly.  Fix them up so we can remove the
presence in kernel.h file.

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

arch/arm/mach-imx/cpu_op-mx51.c

@@ -11,6 +11,7 @@
  * http://www.gnu.org/copyleft/gpl.html
  */
 
+#include <linux/bug.h>
 #include <linux/types.h>
 #include <mach/hardware.h>
 #include <linux/kernel.h>