ARM: dts: rockchip: Update regulator name for PX3

The regulator name of SWITCH_REG1 does not match any other board
with a rk818 PMIC, nor does it correspond to a regulator in the
rk808-regulator driver. Changing name to SWITCH_REG which is
consistent with other boards and is in the driver.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20220303203958.4904-4-macroalpha82@gmail.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>