ESP::ps_malloc check mem availability before allocation.

include/services/esp.hpp

@@ -60,8 +60,11 @@ class ESP
       return adc1_get_raw(channel);
     }
 
-    static void * ps_malloc(uint32_t size) { 
-      void * mem = heap_caps_malloc(size, MALLOC_CAP_SPIRAM); 
+    static void * ps_malloc(uint32_t size) {
+      void * mem = nullptr; 
+      if (heap_caps_get_largest_free_block(MALLOC_CAP_SPIRAM) > size) {
+        mem = heap_caps_malloc(size, MALLOC_CAP_SPIRAM); 
+      }
       if (mem == nullptr) {
         ESP_LOGE(TAG, "Not enough memory on PSRAM!!! (Asking %u bytes)", size);
       }