usb: musb: move otg specific initializations from twl to glue

Moved otg specific state(OTG_STATE_B_IDLE, OTG_STATE_A_IDLE) initializations
from twl to glue. These initializations are removed from twl4030 and
twl6030 and moved to the mailbox API defined in glue.
This is part of the cleanup in preparation to make use of usb2 phy
driver.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>