fix unused parameter warning in vmxnet3_dump_regs()

This fixes:
  external/ethtool/vmxnet3.c:6:43: error: unused parameter 'info' [-Werror,-Wunused-parameter]
  vmxnet3_dump_regs(struct ethtool_drvinfo *info, struct ethtool_regs *regs)

Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I5494339c8d17e72424651e7056605cd61aa6d4b8
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/vmxnet3.c b/vmxnet3.c
index 621d02f..c972145 100644
--- a/vmxnet3.c
+++ b/vmxnet3.c
@@ -3,7 +3,8 @@
 #include "internal.h"
 
 int
-vmxnet3_dump_regs(struct ethtool_drvinfo *info, struct ethtool_regs *regs)
+vmxnet3_dump_regs(struct ethtool_drvinfo *info maybe_unused,
+		  struct ethtool_regs *regs)
 {
 	u32 *regs_buff = (u32 *)regs->data;
 	u32 version = regs->version;