ARM: 6373/1: tc35892-gpio: add setup/remove callbacks

For board-specific initialization.

Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: linux-kernel@vger.kernel.org
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>