staging: hikey9xx: phy-hi3670-usb3: use a consistent namespace

Rename hikey970 to hi3670, in order to use a namespace
similar to hi3660 driver.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/0a2b7d1d1779551be604532a9959237fd3513971.1600338981.git.mchehab+huawei@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>