arm64: dts: ti: k3-j7200-main: Add gpio nodes in main domain

There are 4 instances of gpio modules in main domain:
	gpio0, gpio2, gpio4 and gpio6

Groups are created to provide protection between different processor virtual
worlds. Each of these modules I/O pins are muxed within the group. Exactly
one module can be selected to control the corresponding pin by selecting it
in the pad mux configuration registers.

This group pins out 69 lines (5 banks).

Add DT modes for each module instance in the main domain.

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>