Fix #9361

Marlin/src/inc/Conditionals_post.h

@@ -1120,9 +1120,9 @@
 #endif
 
 /**
- * VIKI2, miniVIKI, and AZSMZ_12864 require DOGLCD_SCK and DOGLCD_MOSI to be defined.
+ * VIKI2, miniVIKI, AZSMZ_12864, and MKS_12864OLED_SSD1306 require DOGLCD_SCK and DOGLCD_MOSI to be defined.
  */
-#if ENABLED(VIKI2) || ENABLED(miniVIKI) || ENABLED(AZSMZ_12864)
+#if ENABLED(VIKI2) || ENABLED(miniVIKI) || ENABLED(AZSMZ_12864) || ENABLED(MKS_12864OLED_SSD1306)
   #ifndef DOGLCD_SCK
     #define DOGLCD_SCK  SCK_PIN
   #endif