USB: usb-storage: use adaptive DMA mask

This patch (as1060) makes usb-storage set the DMA alignment mask for
SCSI slaves to match the maxpacket size of the bulk-IN endpoint,
rather than always setting it to 511.  For full-speed devices that
mask is too restrictive, and wireless USB devices can have maxpacket
sizes larger than 512.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>