ARM: OMAP: gpmc-nand: drop __init annotation

gpmc_nand_init() will be called from another driver's probe() function,
so the easiest way to prevent section mismatches is to drop the
annotation here.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Tony Lindgren <tony@atomide.com>