Display Ender 3 v2 on board MKS robin nano V3.1.

[LoloMake60]

Hello,

Pin update to support board MKS robin nano V3.1 with original Ender3 v2 Display. But you have still to rewire display cable.

Edit pins_MKS_ROBIN_NANO_V3_common.h and add:

#if EITHER(HAS_DWIN_E3V2, IS_DWIN_MARLINUI)
  /**
   *          MKS Robin nano V3.1                       MKS Robin nano V3.1
   *                ------                                     ------
   * (BEEPER)  PC5 |10  9 | PE13 (BTN_ENC)   (SPI1 MISO)  PA6 |10  9 | PA5  (SPI1 SCK)
   * (LCD_EN) PD13 | 8  7 | PC6  (LCD_RS)      (BTN_EN1)  PE8 | 8  7 | PE10 (SPI1 CS)
   * (LCD_D4) PE14   6  5 | PE15 (LCD_D5)      (BTN_EN2) PE11   6  5 | PA7  (SPI1 MOSI)
   * (LCD_D6) PD11 | 4  3 | PD10 (LCD_D7)      (SPI1_RS) PE12 | 4  3 | RESET
   *           GND | 2  1 | 5V                            GND | 2  1 | 3.3V
   *                ------                                     ------
   *                 EXP1                                       EXP2
   */


  #define BTN_ENC                           EXP1_09_PIN //PE13
  #define BTN_EN1                           EXP2_08_PIN //PE8
  #define BTN_EN2                           EXP2_06_PIN //PE11
  #define BEEPER_PIN                        EXP1_10_PIN //PC5