net: phy: Iterate over both registered PHYs and struct phy_driver linker list

net: phy: Iterate over both registered PHYs and struct phy_driver linker list

Introduce U_BOOT_PHY_DRIVER() macro which is used to add struct phy_driver
into a new linker list section containing all compiled in struct phy_driver
drivers. This is so far empty until PHY drivers are converted over to this
macro.

Iterate over both drivers registered using soon to be legacy phy_register()
as well as drivers in the new linker list when looking up a suitable PHY
driver. This way, PHY drivers can be converted over to the new macro one
driver at a time.

The relocation of callbacks for linker list based drivers now happens in
phy_init() call as the drivers are available at that point in time, and
phy_register() is not called for those drivers.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Acked-by: Michal Simek <michal.simek@amd.com>
Tested-by: Michal Simek <michal.simek@amd.com> #microblaze (MANUAL_RELOC)