brcm47xx: suppress printing if a module was found in preinit function.

SVN-Revision: 34653

target/linux/brcm47xx/base-files/lib/preinit/05_init_interfaces_brcm

@@ -21,7 +21,7 @@ check_module () {
 
   insmod "$module" "$params"
   sleep 1
-  grep "^$module" /proc/modules
+  grep "^$module" /proc/modules > /dev/null
   return $?
 }