[SCSI] foce: remove bh disable from fcoe sw transport rcv function

The fcoe sw recive packet function (fcoe_rcv) only ever executes in softirq
context.  Given that, and the fact that no use of the fcoe_rx_list is made in
irq context, its not necessecary to disable bottom halves while actually
receiving the frame.  Convert spin_*_bh calls in that function to their
lock-only equivalents

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vasu Dev <vasu.dev@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>