ARM: dts: stm32: update vbus-supply of usbphyc_port0 on stm32mp157c-ev1

phy-stm32-usbphyc bindings uses a connector node with vbus-supply
property.

[backport from linux 43e55d778a6b]
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>