pinctrl: meson: Use devm_pinctrl_register() for pinctrl registration

Use devm_pinctrl_register() for pin control registration.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Carlo Caione <carlo@endlessm.com>
Cc: Beniamino Galvani <b.galvani@gmail.com>
Cc: Lee Jones <lee.jones@linaro.org>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>