usb: phy: ab8500-usb: fix phy tuning value select logic

The driver supports both ab8500 and ab8505, but the actual phy tuning
values logic sets ab8500 values:

if (!is_ab8500_2p0_or_earlier(ab->ab8500))

which is supposed to set values for ab8500, but incorrectly results true
for ab8505 too.

Fix this by adding an additional is_ab8500(ab->ab8500) check.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Maxime Coquelin <maxime.coquelin@st.com>
Signed-off-by: Fabio Baltieri <fabio.baltieri@linaro.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>