Fix RAMPS + VIKI i2c (#15811)

Marlin/src/lcd/HD44780/ultralcd_HD44780.cpp

@@ -111,6 +111,12 @@ static void createChar_P(const char c, const byte * const ptr) {
   #define LCD_STR_PROGRESS  "\x03\x04\x05"
 #endif
 
+#if ENABLED(LCD_USE_I2C_BUZZER)
+  void MarlinUI::buzz(const long duration, const uint16_t freq) {
+    lcd.buzz(duration, freq);
+  }
+#endif
+
 void MarlinUI::set_custom_characters(const HD44780CharSet screen_charset/*=CHARSET_INFO*/) {
   #if NONE(LCD_PROGRESS_BAR, SHOW_BOOTSCREEN)
     UNUSED(screen_charset);

Marlin/src/lcd/ultralcd.cpp

@@ -61,15 +61,13 @@
   MarlinUI::progress_t MarlinUI::progress_override; // = 0
 #endif
 
-#if HAS_BUZZER
-  #include "../libs/buzzer.h"
+#if ENABLED(PCA9632_BUZZER) || USE_BEEPER
+  #include "../libs/buzzer.h" // for BUZZ() macro
   #if ENABLED(PCA9632_BUZZER)
     #include "../feature/leds/pca9632.h"
   #endif
   void MarlinUI::buzz(const long duration, const uint16_t freq) {
-    #if ENABLED(LCD_USE_I2C_BUZZER)
-      lcd.buzz(duration, freq);
-    #elif ENABLED(PCA9632_BUZZER)
+    #if ENABLED(PCA9632_BUZZER)
       pca9632_buzz(duration, freq);
     #elif USE_BEEPER
       buzzer.tone(duration, freq);

Marlin/src/lcd/ultralcd.h

@@ -153,6 +153,8 @@
 
   #if ENABLED(LCD_I2C_VIKI)
 
+    #include <LiquidTWI2.h>
+
     #define B_I2C_BTN_OFFSET 3 // (the first three bit positions reserved for EN_A, EN_B, EN_C)
 
     // button and encoder bit positions within 'buttons'