arm64: dts: mt2712-evb: Fix usb vbus regulators unit names

Update the names to regulator-usb-p{0-3}-vbus to fix unit_address_vs_reg
warnings for those.

Fixes: 1724f4cc ("arm64: dts: Add USB3 related nodes for MT2712")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20221013152212.416661-7-angelogioacchino.delregno@collabora.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>