arm64: dts: imx8mq-thor96: fix no-mmc property for SDHCI

[ Upstream commit ef10d579 ]

There is no "no-emmc" property, so intention for SD/SDIO only nodes was
to use "no-mmc".

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>