PSRAM: you can have it, and eat it or not eat it

*This patch allows to compile with BOARD_HAS_PSRAM, but not set WLED_USE_PSRAM - reserved pins will be protected, and PSRAM usage will be shown in info.
* if you add `-D WLED_USE_PSRAM_JSON` then PSRAM will be used for some JSON buffers, but not for LEDs and Segments.

wled00/presets.cpp

@@ -52,7 +52,7 @@ static void doSaveState() {
     size_t len = measureJson(*fileDoc) + 1;
     DEBUG_PRINTLN(len);
     // if possible use SPI RAM on ESP32
-    #ifdef WLED_USE_PSRAM
+    #if defined(BOARD_HAS_PSRAM) && (defined(WLED_USE_PSRAM) || defined(WLED_USE_PSRAM_JSON))
     if (psramFound())
       tmpRAMbuffer = (char*) ps_malloc(len);
     else