dt-bindings: phy: Convert st,spear1310-miphy to DT schema

Convert the ST SPEAr MIPHY PHY binding to DT schema format. It's a
straight forward conversion.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20250607212629.744191-1-robh@kernel.org


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