omap3/cpu.h: add BCH support

This patch adds the BCH result registers to register mapping for OMAP3 gpmc.

Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
Cc: Tom Rini <trini@ti.com>
Cc: Ilya Yanok <ilya.yanok@cogentembedded.com>
Cc: Scott Wood <scottwood@freescale.com>
Reviewed-by: Tom Rini <trini@ti.com>