mmc: pwrseq: Use device_match_of_node()

Replace the open-code with device_match_of_node().

Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
Link: https://lore.kernel.org/r/202211171524116446204@zte.com.cn


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>