igb: Rename a variable in igb_receive_internal()

Rename variable "n" to "causes", which properly represents the content
of the variable.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
Signed-off-by: Jason Wang <jasowang@redhat.com>

hw/net/igb_core.c

@@ -1569,7 +1569,7 @@ igb_receive_internal(IGBCore *core, const struct iovec *iov, int iovcnt,
                      bool has_vnet, bool *external_tx)
 {
     uint16_t queues = 0;
-    uint32_t n = 0;
+    uint32_t causes = 0;
     union {
         L2Header l2_header;
         uint8_t octets[ETH_ZLEN];
@@ -1649,28 +1649,28 @@ igb_receive_internal(IGBCore *core, const struct iovec *iov, int iovcnt,
             e1000x_fcs_len(core->mac);
 
         if (!igb_has_rxbufs(core, rxr.i, total_size)) {
-            n |= E1000_ICS_RXO;
+            causes |= E1000_ICS_RXO;
             trace_e1000e_rx_not_written_to_guest(rxr.i->idx);
             continue;
         }
 
-        n |= E1000_ICR_RXDW;
+        causes |= E1000_ICR_RXDW;
 
         igb_rx_fix_l4_csum(core, core->rx_pkt);
         igb_write_packet_to_guest(core, core->rx_pkt, &rxr, &rss_info);
 
         /* Check if receive descriptor minimum threshold hit */
         if (igb_rx_descr_threshold_hit(core, rxr.i)) {
-            n |= E1000_ICS_RXDMT0;
+            causes |= E1000_ICS_RXDMT0;
         }
 
         core->mac[EICR] |= igb_rx_wb_eic(core, rxr.i->idx);
 
         trace_e1000e_rx_written_to_guest(rxr.i->idx);
     }
 
-    trace_e1000e_rx_interrupt_set(n);
-    igb_set_interrupt_cause(core, n);
+    trace_e1000e_rx_interrupt_set(causes);
+    igb_set_interrupt_cause(core, causes);
 
     return orig_size;
 }