arm64: dts: ti: k3-am654-base-board: Add missing pinmux wkup_uart, mcu_uart and mcu_i2c

Many of the definitions depend on pinmux done by the bootloader. Be
explicit about the pinmux for functionality and completeness.

Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Kamlesh Gurudasani <kamlesh@ti.com>
Link: https://lore.kernel.org/r/20230419225913.663448-2-nm@ti.com


Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>