removed ram cache and access flash lut directly

libraries/pico_graphics/pico_graphics_pen_rgb332.cpp

@@ -94,17 +94,6 @@ namespace pimoroni {
     void PicoGraphics_PenRGB332::scanline_convert(PenType type, conversion_callback_func callback) {
         if(type == PEN_RGB565) {
 
-            static RGB565 cache[256];
-            for(auto i = 0u; i < 256; i++) {
-                cache[i] = rgb332_to_rgb565_lut[i]; // defined in pico_graphics.hpp
-            }
-
-            // 2ms slower, I swear!
-            /*
-            static RGB565 cache[256];
-            memcpy(cache, rgb332_to_rgb565_lut, 256 * sizeof(RGB565));
-            */
-
             // Treat our void* frame_buffer as uint8_t
             uint8_t *src = (uint8_t *)frame_buffer;
 
@@ -112,7 +101,8 @@ namespace pimoroni {
             uint16_t row_buf[bounds.w];
             for(auto y = 0; y < bounds.h; y++) {
                 for(auto x = 0; x < bounds.w; x++) {
-                    row_buf[x] = cache[*src];
+                    row_buf[x] = rgb332_to_rgb565_lut[*src];
+
                     src++;
                 }
                 // Callback to the driver with the row data