Fix: allow higher i2s speed

src/ESP32-HUB75-MatrixPanel-I2S-DMA.h

@@ -306,7 +306,7 @@ struct HUB75_I2S_CFG
   bool clkphase;
 
   // Minimum refresh / scan rate needs to be configured on start due to LSBMSB_TRANSITION_BIT calculation in allocateDMAmemory()
-  uint8_t min_refresh_rate;
+  uint16_t min_refresh_rate;
 
   // struct constructor
   HUB75_I2S_CFG(

src/platforms/esp32/esp32_i2s_parallel_dma.cpp

@@ -266,6 +266,8 @@ Modified heavily for the ESP32 HUB75 DMA library by:
 			_div_num = 4;
 		}
 
+    _div_num = 1;
+
 		///auto _div_num = 80000000L/freq;
 
 		ESP_LOGD("ESP32", "i2s pll_d2_clock clkm_div_num is: %u", _div_num);