generic: phy: aquantia: fix MDI pair property parsing

generic: phy: aquantia: fix MDI pair property parsing

of_property_read_u32 returns -EINVAL when property does not exist,
according to the documentation -ENOENT is not a valid return code.

So, instead of checking for -ENOENT check for -EINVAL as otherwise the
blamed commit breaks AQR probe since it will return -EINVAL during probe.

Fixes: cb2a11f49c98 ("generic: phy: aquantia: add pending patch to force MDI pair order")
Link: https://github.com/openwrt/openwrt/pull/16466
Signed-off-by: Robert Marko <robimarko@gmail.com>