usb: phy: phy-generic: export init functions

This patch exports the mostly generic functions so they can be used from
other phy driver instead of duplicating the code.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --cc drivers/usb/phy/phy-generic.c
Simple merge

diff --cc drivers/usb/phy/phy-generic.h
Simple merge