docs: networking: phy: Fix a typo

Write "to be operated" instead of "to be operate".

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20220610072809.352962-1-j.neuschaefer@gmx.net


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