dt-bindings: phy: amlogic,meson-axg-mipi-pcie-analog: remove phy cell parameter

The Amlogic AXG MIPI + PCIe Analog PHY provides function for both PCIe and
MIPI DSI at the same time, and is not exclusive.

Thus remove the invalid phy cell parameter.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20201116101647.73448-3-narmstrong@baylibre.com


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