msm_otg: hack to allow manual usb host mode (externally powered)
Enable debugfs /sys/kernel/debug/msm_otg/mode for manual otg mode manipulation.
Always force requested mode (none, peripheral, host).
Use ID_A bit instead of ID for host mode.

Change-Id: If46de86cebb51c1cff47300dec7acc9f321bf420
Note: There are no provisions for charger detection when setting host mode manually.