mx51_babbage: Fix ckih2 parameter in mx51_clocks_init function

This patch is to be applied into Sascha's mxc-master branch.

Fix ckih2 parameter in mx51_clocks_init funtion. CKIH2 pin is left unconnected on Babbage.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Amit Kucheria <amit.kucheria@canonical.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>