avr32: move hsmc_init() to core_initcall

The board init code, typically running from postcore_initcall, may
need to set up SMC timings. We have to make sure the SMC driver is
ready before this happens.

Signed-off-by: Håvard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>