cxgb4: Delete an unnecessary check before the function call "release_firmware"

The release_firmware() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c

@@ -5142,8 +5142,7 @@ static int adap_init0(struct adapter *adap)
 				 state, &reset);
 
 		/* Cleaning up */
-		if (fw != NULL)
-			release_firmware(fw);
+		release_firmware(fw);
 		t4_free_mem(card_fw);
 
 		if (ret < 0)