arm64: dts: mediatek: mt8173-evb: Fix regulator-fixed node names

Fix a unit_address_vs_reg warning for the USB VBUS fixed regulators
by renaming the regulator nodes from regulator@{0,1} to regulator-usb-p0
and regulator-usb-p1.

Cc: stable@vger.kernel.org
Fixes: c0891284

 ("arm64: dts: mediatek: add USB3 DRD driver")
Link: https://lore.kernel.org/r/20231025093816.44327-8-angelogioacchino.delregno@collabora.com
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>