musb_hdrc: Add support for SRP, HNP and basic host idling

Several changes, mostly affecting tusb:

- Make SRP and HNP mostly work
- Add a timer for handling OTG events
- Add a timeout for turning off VBUS in host mode via sysfs

Only tested on tusb.

Signed-off-by: Tony Lindgren <tony@atomide.com>

diff --cc drivers/usb/musb/g_ep0.c
Simple merge

diff --cc drivers/usb/musb/musb_gadget.c
Simple merge

diff --cc drivers/usb/musb/musb_procfs.c
Simple merge

diff --cc drivers/usb/musb/musbdefs.h
Simple merge

diff --cc drivers/usb/musb/plat_uds.c
Simple merge

diff --cc drivers/usb/musb/tusb6010.c
Simple merge

diff --cc drivers/usb/musb/virthub.c
Simple merge