ANDROID: GKI: Add dual role mode to usb_dr_modes array

This is required for usb_get_dr_mode_from_string() to support
dual role mode.

Test: build, boot
Bug: 150901210
Change-Id: I14ce2481a02648f745a85995c38d75acdbf61a04
(cherry picked from commit d4c4fb2d63ce1f2f7bf07975f71a5a0a4b2f5aec)
Fixes: e203009d("ANDROID: GKI: usb: dwc3: Add USB_DR_MODE_DRD as
dual role mode")
[hridya: partial cherry-pick to fix crash on usb disconnect]
Signed-off-by: Hridya Valsaraju <hridya@google.com>