usb: otg-fsm: add B_AIDL_BDIS timer

Add A-idle to B-disconnect timer, B-device detects that bus is idle
for more than TB_AIDL_BDIS min and begins HNP by turning off pullup
on D+. This allows the bus to discharge to the SE0 state.

Acked-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Li Jun <jun.li@nxp.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>