env: net: Move eth_parse_enetaddr() to net.c/h

This function fits better with the network subsystem, so move it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Suggested-by: Joe Hershberger <joe.hershberger@ni.com>

net/net.c

@@ -1614,3 +1614,15 @@ ushort env_get_vlan(char *var)
 {
 	return string_to_vlan(env_get(var));
 }
+
+void eth_parse_enetaddr(const char *addr, uint8_t *enetaddr)
+{
+	char *end;
+	int i;
+
+	for (i = 0; i < 6; ++i) {
+		enetaddr[i] = addr ? simple_strtoul(addr, &end, 16) : 0;
+		if (addr)
+			addr = (*end) ? end + 1 : end;
+	}
+}