arm64: dts: ti: Add support for AM642 EVM

The AM642 EValuation Module (EVM) is a board that provides access to
various peripherals available on the AM642 SoC, such as PCIe, USB 2.0,
CPSW Ethernet, ADC, and more.

Introduce support for the AM642 EVM to enable mmc boot, including
enabling UART and I2C on the board.

Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Tested-by: Kishon Vijay Abraham I <kishon@ti.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Link: https://lore.kernel.org/r/20210226144257.5470-6-d-gerlach@ti.com