mpc512x: add ifm ac14xx board

Add new mpc5121e based ac14xx board and a new pinmux config
function for setting individual pinmux bit groups. This
function is used in ac14xx board code.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
diff --git a/MAINTAINERS b/MAINTAINERS
index b6c7615..12c38d6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -234,6 +234,7 @@
 
 Anatolij Gustschin <agust@denx.de>
 
+	ac14xx		MPC5121e
 	O2D		MPC5200
 	O2D300		MPC5200
 	O2DNT2		MPC5200