Limit the PSRAM input path to dual wifi + ethernet builds

An ethernet-only build has internal RAM to spare (135 KB free idle on a
CAST-1 built without wifi), so keep stock behaviour there.

esphome/components/ethernet/ethernet_component_esp32.cpp

@@ -74,9 +74,11 @@ static const char *const TAG = "ethernet";
 // PHY register size for hex logging
 static constexpr size_t PHY_REG_SIZE = 2;
 
-// SPI MACs only: the bus is the bottleneck there, the extra copy is unmeasured on the 100 Mbit EMAC.
-// Replacing the glue's input path would bypass its L2 TAP filter, so leave it alone when that is on.
-#if defined(USE_PSRAM) && defined(USE_ETHERNET_SPI) && !CONFIG_ESP_NETIF_L2_TAP
+// Dual wifi + ethernet builds only: wifi's fixed costs leave little internal RAM and its buffers are
+// already in PSRAM, while an ethernet-only build has room to spare. SPI MACs only: the bus is the
+// bottleneck there, the extra copy is unmeasured on the 100 Mbit EMAC. Not with L2 TAP, whose filter
+// lives in the glue's input path.
+#if defined(USE_PSRAM) && defined(USE_ETHERNET_SPI) && defined(USE_WIFI) && !CONFIG_ESP_NETIF_L2_TAP
 #define USE_ETHERNET_RX_PSRAM
 // ESP-IDF ethernet drivers malloc() every received frame in internal RAM, where it stays until lwIP
 // hands it to the application. Move it to PSRAM; if that fails the frame is passed on where it is.

tests/components/ethernet/test-w5500-psram.esp32-s3-idf.yaml

@@ -1,6 +0,0 @@
-# W5500 with PSRAM: compiles the input path that moves received frames to PSRAM
-packages:
-  ethernet: !include common-w5500.yaml
-
-psram:
-  mode: quad

tests/components/ethernet/test-w5500-wifi-psram.esp32-s3-idf.yaml

@@ -0,0 +1,15 @@
+# W5500 next to wifi with PSRAM: compiles the input path that moves received frames to PSRAM
+packages:
+  ethernet: !include common-w5500.yaml
+
+psram:
+  mode: quad
+
+wifi:
+  ssid: MySSID
+  password: password1
+
+network:
+  priority:
+    - ethernet
+    - wifi