USB: usbmon: Implement compat_ioctl

Running a 32-bit usbmon(8) on 2.6.28-rc9 produces the following:
ioctl32(usbmon:28563): Unknown cmd fd(3) cmd(400c9206){t:ffffff92;sz:12} arg(ffd3f458) on /dev/usbmon0

It happens because the compatibility mode was implemented for 2.6.18
and not updated for the fsops.compat_ioctl API.

This patch relocates the pieces from under #ifdef CONFIG_COMPAT into
compat_ioctl with no other changes except one new whitespace.

Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>