net: stmmac: socfpga: Agilex5 EMAC platform configuration

net: stmmac: socfpga: Agilex5 EMAC platform configuration

Agilex5 HPS EMAC uses the dwxgmac-3.10a IP, unlike previous socfpga
platforms which use dwmac1000 IP. Due to differences in platform
configuration, Agilex5 requires a distinct setup.

Introduce a setup_plat_dat() callback in socfpga_dwmac_ops to handle
platform-specific setup. This callback is invoked before
stmmac_dvr_probe() to ensure the platform data is correctly
configured. Also, implemented separate setup_plat_dat() callback for
current socfpga platforms and Agilex5.

Signed-off-by: Rohan G Thomas <rohan.g.thomas@altera.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Tested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20251101-agilex5_ext-v2-1-a6b51b4dca4d@altera.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>