Currently, BG2Q shares a compatible with BG2. This is incorrect, since
BG2 and BG2Q use different USB PLL dividers. In reality, BG2Q shares a
divider with BG2CD. Change BG2Q's USB PHY compatible string to reflect
that.

Cc: <stable@vger.kernel.org> # v4.2.0-
Signed-off-by: Thomas Hebb <tommyhebb@gmail.com>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>