Fix some DOGM warnings (#16363)

Marlin/src/lcd/dogm/dogm_Statusscreen.h

     #define STATUS_LOGO_X 0
   #endif
   #ifndef STATUS_LOGO_Y
-    #define STATUS_LOGO_Y _MIN(0, 10 - (STATUS_LOGO_HEIGHT) / 2)
+    #define STATUS_LOGO_Y _MIN(0U, (10 - (STATUS_LOGO_HEIGHT) / 2))
   #endif
   #ifndef STATUS_LOGO_HEIGHT
     #define STATUS_LOGO_HEIGHT (sizeof(status_logo_bmp) / (STATUS_LOGO_BYTEWIDTH))

Marlin/src/lcd/dogm/status_screen_DOGM.cpp

       UNUSED(blink);
     #endif
 
-    const bool isHeat = BED_ALT();
-
     const uint8_t tx = STATUS_BED_TEXT_X;
 
     const float temp = thermalManager.degBed(),
               target = thermalManager.degTargetBed();
 
+    #if ENABLED(STATUS_HEAT_PERCENT) || (DO_DRAW_BED && DISABLED(STATUS_BED_ANIM))
+      const bool isHeat = BED_ALT();
+    #endif
+
     #if DO_DRAW_BED && DISABLED(STATUS_BED_ANIM)
       #define STATIC_BED    true
       #define BED_DOT       isHeat