It's not so usual, but there are still some cases which require pinctrl
driver function at arch_initcall time.  So register imx23 and imx28
pinctrl driver at postcore_initcall time.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Reviewed-by: NRichard Zhao <richard.zhao@freescale.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>