pinctrl: at91: fix typos

Fix AT91_PINCTRL_DEBOUNCE_VAL dt macro typo.
Fix at91_pinctrl_mux_ops callback typos.

Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>