dt-bindings: mmc: sdhci-msm: add IPQ6018 compatible

IPQ6018 has a sdhci-msm compatible MMC controller. Add the appropriate
compatible to the documentation.

Signed-off-by: Mantas Pucka <mantas@8devices.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1682338412-15420-2-git-send-email-mantas@8devices.com


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