uboot-imx

i.MX28: Add LRADC init to i.MX28 SPL

This code is part of battery boot support for i.MX28.

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Detlev Zundel <dzu@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Wolfgang Denk <wd@denx.de>