usb: host: ehci-omap: fix .remove and failure handling path of .probe(v1)

Obviously, disabling & put regulator and iounmap(hcd->regs)
are missed in .remove and failure handling path of .probe,
so add them.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Keshava Munegowda <Keshava_mgowda@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>