net: phy: broadcom: include phy.h for brcmphy.h

We utilize inline functions from the PHY library, make sure that we do
include phy.h in brcmphy.h in order for the code including brcmphy.h not
to have to resolve this inclusion dependency.

Fixes: 70531479 ("net: phy: broadcom: move shadow 0x1C register accessors to brcmphy.h")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>