net: phy: Remove inline definitions from convinience functions

The convinience functions are not that small and they caused
bloated text segments because of their usage.
There was no need to inline them in the first place, as
they're not part of a fastpath.

Signed-off-by: Ramon Fried <rfried.dev@gmail.com>
Reviewed-by: Michael Trimarchi <michael@amarulasolutions.com>
Reviewed-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>