Move definition of "blink" to main ultralcd file

Marlin/dogm_lcd_implementation.h

 #include "utf_mapper.h"
 
 int lcd_contrast;
-static unsigned char blink = 0; // Variable for visualization of fan rotation in GLCD
 static char currentfont = 0;
 
 static void lcd_setFont(char font_nr) {

Marlin/ultralcd.cpp

   #define ENCODER_DIRECTION_MENUS() ;
 #endif
 
+uint8_t blink = 0; // Variable for animation
+
 int8_t encoderDiff; // updated from interrupt context and added to encoderPosition every LCD update
 
 bool encoderRateMultiplierEnabled;

Marlin/ultralcd.h

 
   extern bool cancel_heatup;
 
+  extern uint8_t blink; // Variable for animation
+
   #if ENABLED(FILAMENT_LCD_DISPLAY)
     extern millis_t previous_lcd_status_ms;
   #endif

Marlin/ultralcd_implementation_hitachi_HD44780.h

 * Implementation of the LCD display routines for a Hitachi HD44780 display. These are common LCD character displays.
 **/
 
-static unsigned char blink = 0; // Variable for animation
 extern volatile uint8_t buttons;  //an extended version of the last checked buttons in a bit array.
 
 ////////////////////////////////////