Fix the invalid BT shutdown GPIO (gpio1_io3 not gpio4_io16)

Fixes: 716ced30 ("arm64: dts: freescale: Add imx8mp-venice-gw73xx-2x")
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>