pinctrl: armada-37xx: Fix uart2 group selection register mask

pinctrl: armada-37xx: Fix uart2 group selection register mask

If north bridge selection register bit1 is clear, pins [10:8] are for
SDIO0 Resetn, Wakeup, and PDN while if bit1 is set, pins [10:8]are for
GPIO; when bit1 is clear, pin 9 and pin 10 can be used for uart2 RTSn
and CTSn, so bit1 should be added to uart2 group and it must be set
for both "gpio" and "uart" functions of uart2 group.

Signed-off-by: Ken Ma <make@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>