p54usb: Remove DMA buffer from stack

On 2.6.32-rc6 from wireless-testing, the following warning is emitted:

------------[ cut here ]------------
WARNING: at lib/dma-debug.c:860 check_for_stack+0xaa/0xe0()
Hardware name: HP Pavilion dv2700 Notebook PC
ehci_hcd 0000:00:02.1: DMA-API: device driver maps memory fromstack
	 [addr=ffff8800b6e2bca8]
Modules linked in: <Removed>
Pid: 16378, comm: modprobe Not tainted 2.6.32-rc6-wl #244
Call Trace:
 [<ffffffff81049698>] warn_slowpath_common+0x78/0xb0
 [<ffffffff8104972c>] warn_slowpath_fmt+0x3c/0x40
 [<ffffffff811ae52a>] check_for_stack+0xaa/0xe0
 [<ffffffff811afc8d>] debug_dma_map_page+0xfd/0x170
 [<ffffffffa006297a>] usb_hcd_submit_urb+0x3da/0x9c0 [usbcore]
 [<ffffffff81076e6f>] ? lockdep_init_map+0x5f/0x5d0
 [<ffffffffa0063365>] usb_submit_urb+0xe5/0x260 [usbcore]
 [<ffffffffa0064b7e>] usb_start_wait_urb+0x5e/0xf0 [usbcore]
 [<ffffffffa0063943>] ? usb_init_urb+0x23/0x40 [usbcore]
 [<ffffffffa0064cd4>] usb_bulk_msg+0xc4/0x150 [usbcore]
 [<ffffffffa0441a91>] T.719+0x31/0x40 [p54usb]
 [<ffffffffa0441acf>] p54u_upload_firmware_3887+0x2f/0x490 [p54usb]
 [<ffffffffa049c667>] ? p54_parse_firmware+0x427/0x450 [p54common]
 <Rest of traceback removed>
---[ end trace f77df0316ddad3de ]---

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Stable <stable@vger.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>