netxen_nic: Replace fake flex-array with flexible-array member

Zero-length arrays as fake flexible arrays are deprecated and we are moving towards adopting C99 flexible-array members instead.

Transform zero-length array into flexible-array member in struct nx_cardrsp_rx_ctx_t.

Address the following warnings found with GCC-13 and
-fstrict-flex-arrays=3 enabled:
drivers/net/ethernet/qlogic/netxen/netxen_nic_ctx.c:361:26: warning: array subscript <unknown> is outside array bounds of ‘char[0]’ [-Warray-bounds=] drivers/net/ethernet/qlogic/netxen/netxen_nic_ctx.c:372:25: warning: array subscript <unknown> is outside array bounds of ‘char[0]’ [-Warray-bounds=]

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE routines on memcpy() and help us make progress towards globally enabling -fstrict-flex-arrays=3 [1].

---
 drivers/net/ethernet/qlogic/netxen/netxen_nic.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index f13fa7396aef..3d36d23df0c6 100644
@@ -854,7 +854,7 @@ typedef struct {
 	   The following is packed:
 	   - N cardrsp_rds_rings
 	   - N cardrs_sds_rings */
-	char data[0];
+	char data[];
 } nx_cardrsp_rx_ctx_t;
 
 #define SIZEOF_HOSTRQ_RX(HOSTRQ_RX, rds_rings, sds_rings)	\

2.34.1