usb: core: Re-try enumeration in FS if high speed enumeration fails

If chirping sequence to detect high speed device fails to complete
device fails to enumerate. In order to prevent device enumeration
failure, disable high speed chirping which allows device to
re-enumerate in full speed mode. Re-enable high speed chirping once
device speed is known.

Change-Id: I8c2d36ea93216372f047303d9b15e45da9fcedc5
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>