Add MKS_12864OLED to lcd_implementation_init

Followup to #7914

Marlin/src/lcd/ultralcd_impl_DOGM.h

 // Initialize or re-initialize the LCD
 static void lcd_implementation_init() {
 
+  #if ENABLED(MKS_12864OLED) || ENABLED(MKS_12864OLED_SSD1306)
+    SET_OUTPUT(LCD_PINS_DC);
+    OUT_WRITE(LCD_PINS_RS, LOW);
+    delay(1000);
+    WRITE(LCD_PINS_RS, HIGH);
+  #endif
+
   #if PIN_EXISTS(LCD_BACKLIGHT) // Enable LCD backlight
     OUT_WRITE(LCD_BACKLIGHT_PIN, HIGH);
   #endif