mmc: sdhci-of-arasan: Add Support for Intel LGM SDXC

The current arasan sdhci PHY configuration isn't compatible
with the PHY on Intel's LGM(Lightning Mountain) SoC devices.

Therefore, add a new compatible, to adapt the Intel's LGM
SDXC PHY with arasan-sdhc controller to configure the PHY.

Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>