[SCSI] fnic: Change fnic_flush_tx() to flush tx instead of rx queue

fnic_flush_tx() is used to send frames held while fabric login
is in progress.  The frames are held in tx_queue, but
fnic_flush_tx() was incorrectly flushing from recv_queue which
is used for received frames.

Signed-off-by: Brian Uchino <buchino@cisco.com>
Signed-off-by: Abhijeet Joglekar <abjoglek@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>