msm_otg: hack to allow externally powered usb host mode

Force ID_A (host mode + charging) on detection of proprietary charger (Apple-compatible charger with voltage on D+/D-).
Unforce ID_A on PMIC: BSV clear (detection of loss of charger).
Simulate ACA since using ID_A for host mode (prevents host from getting stuck in suspended state).
Two test cases for detection of actual proprietary charger (extra debug output for now).
Remove charge current limit in host mode (ID_A).
Enable debugfs /sys/kernel/debug/msm_otg/mode for manual otg mode manipulation.
Always force requested mode (debugfs).

Note: ID pin detection not working (perhaps due to Slimport), hence the "alternate" triggers used to switch to/from host mode.
msm_otg: move ID_A forcing to ACA detection (workaround for proprietary chargers)
Move ID_A forcing to ACA detect so that automatic host mode can be disabled by disabling ACA (# echo disable > /sys/kernel/debug/msm_otg/aca).
No longer need to simulate ACA since (debug) ACA will now be forced.
Remove test cases for actual proprietary chargers since they were causing false positives (manually disable ACA to use proprietary chargers).
msm_otg: start charging immediately when entering host mode (compatibility with proprietary chargers)
msm_otg: fix bad if-statement in last commit