cmd: bootvx: Pass netmask and gatewayip to VxWorks bootline

There are fields in VxWorks bootline for netmask and gatewayip.
We can get these from U-Boot environment variables and pass them
to VxWorks, just like ipaddr and serverip.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/cmd_elf.c b/common/cmd_elf.c
index 6c95851..6a09378 100644
--- a/common/cmd_elf.c
+++ b/common/cmd_elf.c
@@ -288,13 +288,26 @@
 				       CONFIG_SYS_VXWORKS_SERVERNAME);
 
 		tmp = getenv("ipaddr");
-		if (tmp)
-			ptr += sprintf(build_buf + ptr, "e=%s ", tmp);
+		if (tmp) {
+			ptr += sprintf(build_buf + ptr, "e=%s", tmp);
+			tmp = getenv("netmask");
+			if (tmp) {
+				__be32 addr = getenv_ip("netmask").s_addr;
+				ptr += sprintf(build_buf + ptr, ":%08x ",
+					       ntohl(addr));
+			} else {
+				ptr += sprintf(build_buf + ptr, " ");
+			}
+		}
 
 		tmp = getenv("serverip");
 		if (tmp)
 			ptr += sprintf(build_buf + ptr, "h=%s ", tmp);
 
+		tmp = getenv("gatewayip");
+		if (tmp)
+			ptr += sprintf(build_buf + ptr, "g=%s ", tmp);
+
 		tmp = getenv("hostname");
 		if (tmp)
 			ptr += sprintf(build_buf + ptr, "tn=%s ", tmp);