ARM: dts: bcm2711-rpi-4-b: Set dwc2 mode as peripheral

ARM: dts: bcm2711-rpi-4-b: Set dwc2 mode as peripheral

If dwc2 mode is set to otg, forcing dwc2 mode as peripheral is
proceeded in the early boot time, but since tizen configures the
gadget with configfs after system is prepared. It causes enumeration
problem. To prevent it, default mode will be fixed as peripheral.
Actully, since type-c usb port is only used as power-source and
peripheral port, it is more precise setting though.

Change-Id: I78bc6c683c4d095283219b1ab3066fbe7d0c6e53
Signed-off-by: Dongwoo Lee <dwoo08.lee@samsung.com>