arm64: dts: imx8mq-thor96: Fix sdio-pwrseq GPIO property

As per mmc-pwrseq-simple.yaml, the correct way to describe the GPIO
is by using the 'reset-gpios' property.

Change it accordingly to fix the following schema warning:

imx8mq-thor96.dtb: sdio-pwrseq: 'gpio' does not match any of the regexes: 'pinctrl-[0-9]+'
	from schema $id: http://devicetree.org/schemas/mmc/mmc-pwrseq-simple.yaml#



Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>