pinctrl: at91: fix sam9x5 debounce/deglitch functions

Replace at91_mux_get_deglitch with at91_mux_pio3_get_deglitch when using
sam9x5 (pio3) IP.
at91_mux_get_deglitch only test the activation of the "Input Filter" which
may be overloaded by the activation of the "Input Filter Slow Clock" to use
the input filter as a debounce filter instead of a deglitch filter.

Fix at91_mux_pio3_get_debounce to test the activation of the Input Filter
before testing the activation of the debounce filter (Input Filter Slow
Clock depends on Input Filter).

Fix at91_mux_pio3_set_debounce function to avoid disabling the deglitch
filter ("Input Filter") when debounce filter is disabled.

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>