net: hibmcge: select FIXED_PHY

hibmcge uses fixed_phy_register() et al, but doesn't cater for the case
that hibmcge is built-in and fixed_phy is a module. To solve this
select FIXED_PHY.

Fixes: 1d7cd7a9 ("net: hibmcge: support scenario without PHY")
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jijie Shao <shaojijie@huawei.com>
Link: https://patch.msgid.link/c4fc061f-b6d5-418b-a0dc-6b238cdbedce@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>