[MIPS] rbhma4500: use generic txx9 gpio

Use generic txx9 gpio (and gpiolib) for RBHMA4500 board.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
3 files changed