soc: ti: pruss: Enable support for ICSSG subsystems on K3 AM64x SoCs

soc: ti: pruss: Enable support for ICSSG subsystems on K3 AM64x SoCs

The K3 AM64x family of SoCs have a similar version of the PRU-ICSS (ICSSG)
processor subsystem present on K3 J721E and K3 AM65x SR2.0 SoCs. These SoCs
contain typically two ICSSG instances named ICSSG0 and ICSSG1. The two
ICSSGs are identical to each other for the most part with minor SoC
integration differences and capabilities. SGMII mode is not supported at
all on these SoCs (unlike specific instances on AM65x, J721E). The ICSSG1
also has limited pins connected on some sub-modules compared to ICSSG0.

There is no change in the Interrupt Controller w.r.t either of AM65x or
J721E SoCs. All other integration aspects are also very similar to the
existing SoCs.

The existing pruss platform driver has been updated to support these
similar ICSSG instances through a new AM64x specific compatible.

Signed-off-by: Suman Anna <s-anna@ti.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>