net: phy: aquantia: rename and export aqr107_wait_reset_complete()

This function is quite generic in this driver and not limited to aqr107.
We will use it outside its current compilation unit soon so rename it
and declare it in the header.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>