net: ti: icssm-prueth: Adds ICSSM Ethernet driver

net: ti: icssm-prueth: Adds ICSSM Ethernet driver

Updates Kernel configuration to enable PRUETH driver and its dependencies
along with makefile changes to add the new PRUETH driver.

Changes includes init and deinit of ICSSM PRU Ethernet driver including
net dev registration and firmware loading for DUAL-MAC mode running on
PRU-ICSS2 instance.

Changes also includes link handling, PRU booting, default firmware loading
and PRU stopping using existing remoteproc driver APIs.

Reviewed-by: Mohan Reddy Putluru <pmohan@couthit.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Basharath Hussain Khaja <basharath@couthit.com>
Signed-off-by: Parvathi Pudi <parvathi@couthit.com>
Link: https://patch.msgid.link/20250912104741.528721-3-parvathi@couthit.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>