dt-bindings: phy: Add eDP PHY compatible for sc7280

Add compatible string for the supported eDP PHY on sc7280 platform.

Signed-off-by: Sankeerth Billakanti <quic_sbillaka@quicinc.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20220207161612.REPOST.v1.1.Iee1d505f0a35c2805f0468625b117d2e0f0ad339@changeid


Signed-off-by: Vinod Koul <vkoul@kernel.org>