scsi: csiostor: fix use after free in csio_hw_use_fwconfig()

mbp pointer is passed to csio_hw_validate_caps() so call mempool_free()
after calling csio_hw_validate_caps().

Signed-off-by: Varun Prakash <varun@chelsio.com>
Fixes: 541c571 ("csiostor:Use firmware version from cxgb4/t4fw_version.h")
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: Varun Prakash

drivers/scsi/csiostor/csio_hw.c

@@ -1769,7 +1769,6 @@ csio_hw_use_fwconfig(struct csio_hw *hw, int reset, u32 *fw_cfg_param)
 		goto bye;
 	}
 
-	mempool_free(mbp, hw->mb_mempool);
 	if (finicsum != cfcsum) {
 		csio_warn(hw,
 		      "Config File checksum mismatch: csum=%#x, computed=%#x\n",
@@ -1780,6 +1779,10 @@ csio_hw_use_fwconfig(struct csio_hw *hw, int reset, u32 *fw_cfg_param)
 	rv = csio_hw_validate_caps(hw, mbp);
 	if (rv != 0)
 		goto bye;
+
+	mempool_free(mbp, hw->mb_mempool);
+	mbp = NULL;
+
 	/*
 	 * Note that we're operating with parameters
 	 * not supplied by the driver, rather than from hard-wired