arm64: dts: ti: j721e-common-proc-board: Add Support for eMMC and SD card

sdhci0 is connected to an eMMC and sdhci1 is connected to an SD card
slot. Add support for these nodes.

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>