arm64: dts: renesas: salvator-common: add pfc node for USB3.0 channel 0

Since a R-Car Gen3 bootloader enables the PFC of USB3.0 channel 0,
the USB3.0 host controller works without this setting on the kernel.
But, this setting should have salvator-common.dtsi. So, this patch
adds the pfc node for USB3.0 channel 0.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>