Revert "usb: musb: musb_host: Enable HCD_BH flag to handle urb return in bottom half"

This reverts commit 20357720.

Commit 20357720 claims throughput improvement for MSC/UVC, but I
don't see much improvement. Following are the MSC measurement using
dd on AM335x GP EVM.

with BCD_BH:    read: 14.9MB/s, write: 20.9MB/s
without BCD_BH: read: 15.2MB/s, write: 21.2MB/s

However with this commit the following regressions have been observed.

1. ASIX usb-ethernet dongle is completely broken on UDP RX.

2. Unpluging a 3G modem, which uses option driver, behind a hub causes
   console log flooding with the following message.

   option_instat_callback: error -71

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>