Fix #276

Fixes warning/error that is only reported with certain compiler warning flag settings ("All" in Arduino IDE).

TFT_eSPI.cpp

@@ -1251,7 +1251,7 @@ void TFT_eSPI::pushImage(int32_t x, int32_t y, uint32_t w, uint32_t h, uint8_t *
           //else     drawPixel((dw-len)+xp,h-dh,bitmap_bg);
           xp++;
         }
-        *ptr++;
+        ptr++;
         len -= 8;
       }
 
@@ -1400,7 +1400,7 @@ void TFT_eSPI::pushImage(int32_t x, int32_t y, uint32_t w, uint32_t h, uint8_t *
           px++;
           xp++;
         }
-        *ptr++;
+        ptr++;
         len -= 8;
       }
       if (np) pushColor(bitmap_fg, np);