efi_loader: Let networking support depend on NETDEVICES

CONFIG_NET does not imply that there are actually network devices
available, only CONFIG_NETDEVICES does. Changing to this dependency
obsoletes the check in Kconfig because NETDEVICES means DM_ETH.

Fixes: 0efe1bcf5c2c ("efi_loader: Add network access support")
Suggested-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/net/bootp.c b/net/bootp.c
index b260d5d..6c01e38 100644
--- a/net/bootp.c
+++ b/net/bootp.c
@@ -1077,7 +1077,9 @@
 			    strlen(CONFIG_SYS_BOOTFILE_PREFIX)) == 0) {
 #endif	/* CONFIG_SYS_BOOTFILE_PREFIX */
 			dhcp_packet_process_options(bp);
-			efi_net_set_dhcp_ack(pkt, len);
+			if (CONFIG_IS_ENABLED(EFI_LOADER) &&
+			    CONFIG_IS_ENABLED(NET_DEVICES))
+				efi_net_set_dhcp_ack(pkt, len);
 
 #if defined(CONFIG_SERVERIP_FROM_PROXYDHCP)
 			if (!net_server_ip.s_addr)