arm64: dts: rockchip: Add some pins for NanoPi4

arm64: dts: rockchip: Add some pins for NanoPi4

The NanoPi4 boards have the RK808's always-on 32KHz clock wired to the
SoC, so have it claim the relevant pinctrl to actually enable the
CLK32K_IN input. The RK808's SLEEP pin is also wired to the SoC's
AP_PWROFF output, so we may as well claim that too.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/e870284a872567f163868b77267c01b77ed6f22a.1647381986.git.robin.murphy@arm.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>