pinctrl: pxa: Use devm_pinctrl_register() for pinctrl registration

Use devm_pinctrl_register() for pin control registration and clean
the error path.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Daniel Mack <daniel@zonque.org>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>