arm64: dts: ti: k3-am69-sk: Add pinmux for RPi Header

Add pinmux required to bring out the i2c and gpios on 40 pin RPi
expansion header on AM69 SK board.

Signed-off-by: Dasnavis Sabiya <sabiya.d@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Udit Kumar <u-kumar1@ti.com>
Link: https://lore.kernel.org/r/20230602214937.2349545-9-nm@ti.com


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