phy: add phy fixup unregister functions

>From : Woojung Huh <woojung.huh@microchip.com>

Add functions to unregister phy fixup for modules.

int phy_unregister_fixup(const char *bus_id, u32 phy_uid, u32 phy_uid_mask)
	Unregister phy fixup from phy_fixup_list per bus_id, phy_uid &
	phy_uid_mask

int phy_unregister_fixup_for_uid(u32 phy_uid, u32 phy_uid_mask)
	Unregister phy fixup from phy_fixup_list.
	Use it for fixup registered by phy_register_fixup_for_uid()

int phy_unregister_fixup_for_id(const char *bus_id)
	Unregister phy fixup from phy_fixup_list.
	Use it for fixup registered by phy_register_fixup_for_id()

Signed-off-by: Woojung Huh <woojung.huh@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>