staging: MIPS: add Octeon USB HCD support

Add support for Octeon USB HCD. Tested on EdgeRouter Lite with USB
mass storage.

The driver has been extracted from GPL sources of EdgeRouter Lite firmware
(based on Linux 2.6.32.13). Some minor fixes and cleanups have been done
to make it work with 3.10-rc3.

$ uname -a
Linux (none) 3.10.0-rc3-edge-00005-g86cb5bc #41 SMP PREEMPT Sat Jun 1 20:41:46 EEST 2013 mips64 GNU/Linux
$ modprobe octeon-usb
[   37.971683] octeon_usb: module is from the staging directory, the quality is unknown, you have been warned.
[   37.983649] OcteonUSB: Detected 1 ports
[   37.999360] OcteonUSB OcteonUSB.0: Octeon Host Controller
[   38.004847] OcteonUSB OcteonUSB.0: new USB bus registered, assigned bus number 1
[   38.012332] OcteonUSB OcteonUSB.0: irq 122, io mem 0x00000000
[   38.019970] hub 1-0:1.0: USB hub found
[   38.023851] hub 1-0:1.0: 1 port detected
[   38.028101] OcteonUSB: Registered HCD for port 0 on irq 122
[   38.391443] usb 1-1: new high-speed USB device number 2 using OcteonUSB
[   38.586922] usb-storage 1-1:1.0: USB Mass Storage device detected
[   38.597375] scsi0 : usb-storage 1-1:1.0
[   39.604111] scsi 0:0:0:0: Direct-Access              USB DISK 2.0     PMAP PQ: 0 ANSI: 4
[   39.619113] sd 0:0:0:0: [sda] 7579008 512-byte logical blocks: (3.88 GB/3.61 GiB)
[   39.630696] sd 0:0:0:0: [sda] Write Protect is off
[   39.635945] sd 0:0:0:0: [sda] No Caching mode page present
[   39.641464] sd 0:0:0:0: [sda] Assuming drive cache: write through
[   39.651341] sd 0:0:0:0: [sda] No Caching mode page present
[   39.656917] sd 0:0:0:0: [sda] Assuming drive cache: write through
[   39.664296]  sda: sda1 sda2
[   39.675574] sd 0:0:0:0: [sda] No Caching mode page present
[   39.681093] sd 0:0:0:0: [sda] Assuming drive cache: write through
[   39.687223] sd 0:0:0:0: [sda] Attached SCSI removable disk

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: David Daney <ddaney.cavm@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>