pinctrl: sirf: Remove gpiochip on failure cases

This patch releases gpiochip related resources by calling
gpiochip_remove when gpiochip_irqchip_add fails.

CC: Linus Walleij <linus.walleij@linaro.org>
CC: Barry Song <Baohua.Song@csr.com>
CC: Rongjun Ying <rongjun.ying@csr.com>
CC: Yuping Luo <yuping.luo@csr.com>
Signed-off-by: Pramod Gurav <pramod.gurav@smartplayin.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>