net: dhcp: Allow "MAY_FAIL" to still try each adapter

This change allows the "MAY_FAIL" DHCP option to still attempt to
contact a DHCP server on each adapter and only give up once each
adapter has failed once.  To get the existing behavior, set the
already-existing ethrotate=no variable.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Cc: Keng Soon Cheah <keng.soon.cheah@ni.com>
Cc: Chen Yee Chew <chen.yee.chew@ni.com>

net/bootp.c

@@ -386,12 +386,19 @@ static void bootp_timeout_handler(void)
 
 	if (time_taken >= time_taken_max) {
 #ifdef CONFIG_BOOTP_MAY_FAIL
-		puts("\nRetry time exceeded\n");
-		net_set_state(NETLOOP_FAIL);
-#else
-		puts("\nRetry time exceeded; starting again\n");
-		net_start_again();
+		char *ethrotate;
+
+		ethrotate = env_get("ethrotate");
+		if ((ethrotate && strcmp(ethrotate, "no") == 0) ||
+		    net_restart_wrap) {
+			puts("\nRetry time exceeded\n");
+			net_set_state(NETLOOP_FAIL);
+		} else
 #endif
+		{
+			puts("\nRetry time exceeded; starting again\n");
+			net_start_again();
+		}
 	} else {
 		bootp_timeout *= 2;
 		if (bootp_timeout > 2000)