UPSTREAM: phy: Add reset callback

The only use for this is for solving a hardware design problem in
usb of Rockchip RK3288.

Change-Id: I40b17f5c33125c77759808720763d2694dfc25f2
Signed-off-by: Randy Li <ayaka@soulik.info>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Huang, Tao <huangtao@rock-chips.com>
(cherry picked from commit cac18ecb6f44b11bc303d7afbae3887b27938fa4)