net: ti: icssg-prueth: Add ICSSG Ethernet driver for AM65x SR1.0 platforms

commit 17bf695f7dd1427221ce65f81ccaeeae8dfbd40d from
git://git.ti.com/ti-linux-kernel/ti-linux-kernel.git

commit f5f3bcb99e5718a7415157b0d1e4395e18780f06 upstream

Add the PRUeth driver for the ICSSG subsystem found in AM65x SR1.0 devices.
The main differences that set SR1.0 and SR2.0 apart are the missing TXPRU
core in SR1.0, two extra DMA channels for management purposes and different
firmware that needs to be configured accordingly.

Based on the work of Roger Quadros, Vignesh Raghavendra and
Grygorii Strashko in TI's 5.10 SDK [1].

[1]: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/?h=ti-linux-5.10.y



Co-developed-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Diogo Ivo <diogo.ivo@siemens.com>
Reviewed-by: MD Danish Anwar <danishanwar@ti.com>
Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
Signed-off-by: Xulin Sun <xulin.sun@windriver.com>