rt2860sta: Fix argument to linux_pci_unmap_single()

rt2860sta: Fix argument to linux_pci_unmap_single()

John Halton wrote in <http://bugs.debian.org/575726>:
> Whenever wpa_supplicant is deactivated (whether by killing the process or
> during a normal shutdown) I am getting a kerneloops that prevents the
> computer from completing shutdown. Here is the relevant syslog output:

The backtrace points to an incorrect call from RTMPFreeTxRxRingMemory()
into linux_pci_unmap_single().  This appears to have been fixed in Linux
2.6.33 by this change:

commit ca97b8388838ee9ea4b4bad04948f8f7f8a607a3
Author: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Date:   Tue Sep 22 20:44:07 2009 +0200

    Staging: rt28x0: updates from vendor's V2.1.0.0 drivers

For stable-2.6.32, just fix this one function call.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>