net: fec: make FIXED_PHY dependency unconditional

net: fec: make FIXED_PHY dependency unconditional

When CONFIG_FIXED_PHY is in a loadable module, the fec driver cannot be
built-in any more:

x86_64-linux-ld: vmlinux.o: in function `fec_enet_mii_probe':
fec_main.c:(.text+0xc4f367): undefined reference to `fixed_phy_unregister'
x86_64-linux-ld: vmlinux.o: in function `fec_enet_close':
fec_main.c:(.text+0xc59591): undefined reference to `fixed_phy_unregister'
x86_64-linux-ld: vmlinux.o: in function `fec_enet_mii_probe.cold':

Select the fixed phy support on all targets to make this build
correctly, not just on coldfire.

Notat that Essentially the stub helpers in include/linux/phy_fixed.h
cannot be used correctly because of this build time dependency,
and we could just remove them to hit the build failure more often
when a driver uses them without the 'select FIXED_PHY'.

Fixes: dc86b621e1b4 ("net: fec: register a fixed phy using fixed_phy_register_100fd if needed")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260402141048.2713445-1-arnd@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>