qed: initialize return rc to avoid returning garbage

in the case where qed_slowpath_irq_req is not called, rc is not
assigned and so qed_int_igu_enable will return a garbage value.
Fix this by initializing rc to 0.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NYuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qed/qed_int.c

@@ -2750,7 +2750,7 @@ void qed_int_igu_enable_int(struct qed_hwfn *p_hwfn,
 int qed_int_igu_enable(struct qed_hwfn *p_hwfn, struct qed_ptt *p_ptt,
 		       enum qed_int_mode int_mode)
 {
-	int rc;
+	int rc = 0;
 
 	/* Configure AEU signal change to produce attentions */
 	qed_wr(p_hwfn, p_ptt, IGU_REG_ATTENTION_ENABLE, 0);