pinctrl: airoha: an7583: fix misprint in gpio19 pinconf

pinctrl: airoha: an7583: fix misprint in gpio19 pinconf

[ Upstream commit a7f3e2b7730fc1d6c7431af49e0dc1ee97589795 ]

Pin 21 (gpio19) duplicate pinconf settings of pin 20. Fix it using
a proper bit number in the configuration register.

Fixes: 3ffeb17a9a27 ("pinctrl: airoha: add support for Airoha AN7583 PINs")
Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>