Charger Mod/Fix for Next Rev Hardware: Use OTG function of MP2650

As noted by @zeha , MPS MP2650 charger IC has an OTG mode that can output the 5V itself. So we can get rid of D11 on the motherboard which would help with diode drop of the PD input voltage, and we might not need U12 and USB_SRC_EN at all.

Edit: D11 seems superfluous in general.

Note: per MPS datasheet, OTG pin should be either tied high or be under sysctl control.

TODO: Would this play nicely with @NanoCodeBug 's PD state machine rewrite?