phy: Fix off-by-one error when parsing DT PHY bindings

The code fails to copy the last PHY phandle argument, so it is
missing from the adjusted phandle args and the consumer cannot
use it to determine what the PHY should do.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Patrice Chotard <patrice.chotard@st.com>