simplify NET_LEGACY || NET_LWIP condition with NET condition

Since the move to make NET a menuconfig and NO_NET a synonym of NET=n,
when NET is enabled, NET_LEGACY || NET_LWIP is necessarily true, so
let's simplify the various checks across the codebase.

SPL_NET_LWIP doesn't exist but SPL_NET_LEGACY is an alias for SPL_NET so
the proper symbol is still defined in SPL whenever needed.

Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

common/Kconfig

@@ -425,7 +425,7 @@ config LOGF_FUNC_PAD
 
 config LOG_SYSLOG
 	bool "Log output to syslog server"
-	depends on NET_LEGACY || NET_LWIP
+	depends on NET
 	help
 	  Enables a log driver which broadcasts log records via UDP port 514
 	  to syslog servers.

common/board_r.c

@@ -495,7 +495,7 @@ static int initr_boot_led_on(void)
 	return 0;
 }
 
-#if CONFIG_IS_ENABLED(NET_LEGACY) || CONFIG_IS_ENABLED(NET_LWIP)
+#if CONFIG_IS_ENABLED(NET)
 static int initr_net(void)
 {
 	puts("Net:   ");
@@ -756,7 +756,7 @@ static void initcall_run_r(void)
 #if CONFIG_IS_ENABLED(PCI_ENDPOINT)
 	INITCALL(pci_ep_init);
 #endif
-#if CONFIG_IS_ENABLED(NET_LEGACY) || CONFIG_IS_ENABLED(NET_LWIP)
+#if CONFIG_IS_ENABLED(NET)
 	WATCHDOG_RESET();
 	INITCALL(initr_net);
 #endif