phy: econet: Add PCIe PHY driver for EcoNet EN751221 and EN7528 SoCs.

phy: econet: Add PCIe PHY driver for EcoNet EN751221 and EN7528 SoCs.

Introduce support for EcoNet PCIe PHY controllers found in EN751221
and EN7528 SoCs, these SoCs are not identical but are similar, each
having one Gen1 port, and one Gen1/Gen2 port.

Co-developed-by: Ahmed Naseef <naseefkm@gmail.com>
Signed-off-by: Ahmed Naseef <naseefkm@gmail.com>
[cjd@cjdns.fr: add EN751221 support and refactor for clarity]
Signed-off-by: Caleb James DeLisle <cjd@cjdns.fr>
Link: https://patch.msgid.link/20260425173642.406089-3-cjd@cjdns.fr
Signed-off-by: Vinod Koul <vkoul@kernel.org>