Add FYSETC 2.42 inch OLED support (#18485)

Marlin/src/lcd/dogm/ultralcd_DOGM.cpp

@@ -246,7 +246,7 @@ void MarlinUI::init_lcd() {
       OUT_WRITE(LCD_BACKLIGHT_PIN, DISABLED(DELAYED_BACKLIGHT_INIT)); // Illuminate after reset or right away
     #endif
 
-    #if EITHER(MKS_12864OLED, MKS_12864OLED_SSD1306)
+    #if EITHER(MKS_12864OLED, MKS_12864OLED_SSD1306, FYSETC_242_OLED_12864)
       SET_OUTPUT(LCD_PINS_DC);
       #ifndef LCD_RESET_PIN
         #define LCD_RESET_PIN LCD_PINS_RS

Marlin/src/lcd/dogm/ultralcd_DOGM.h

@@ -123,6 +123,18 @@
     #define U8G_CLASS U8GLIB_SH1106_128X64                      // 8 stripes
   #endif
 
+#elif ENABLED(FYSETC_242_OLED_12864)
+  
+  // FYSETC OLED 2.42" 128 × 64 FULL GRAPHICS CONTROLLER
+      
+  #define FORCE_SOFT_SPI                                        // SW-SPI
+  
+  #if ENABLED(ALTERNATIVE_LCD)
+    #define U8G_CLASS U8GLIB_SSD1306_128X64_2X                  // 4 stripes
+  #else
+    #define U8G_CLASS U8GLIB_SSD1306_128X64                     // 8 stripes
+  #endif
+
 #elif ENABLED(U8GLIB_SH1106)
 
   // Generic SH1106 OLED I2C LCD