🩹 Update BTT GTR v1.0 DIAG jumper/pin (MarlinFirmware#26764)

Author: thisiskeithb

Marlin/src/inc/Warnings.cpp

@@ -681,7 +681,8 @@
 #if !USE_SENSORLESS
   #if ENABLED(USES_DIAG_JUMPERS) && DISABLED(DIAG_JUMPERS_REMOVED)
     #warning "Motherboard DIAG jumpers must be removed when SENSORLESS_HOMING is disabled. (Define DIAG_JUMPERS_REMOVED to suppress this warning.)"
-  #elif ENABLED(USES_DIAG_PINS) && DISABLED(DIAG_PINS_REMOVED)
+  #endif
+  #if ENABLED(USES_DIAG_PINS) && DISABLED(DIAG_PINS_REMOVED)
     #warning "Driver DIAG pins must be physically removed unless SENSORLESS_HOMING is enabled. (See https://bit.ly/2ZPRlt0) (Define DIAG_PINS_REMOVED to suppress this warning.)"
   #endif
 #endif

Marlin/src/pins/stm32f4/pins_BTT_GTR_V1_0.h

@@ -31,7 +31,7 @@
 
 #define BOARD_INFO_NAME "BTT GTR V1.0"
 
-#define USES_DIAG_JUMPERS
+#define USES_DIAG_PINS                            // DIAG jumpers rendered useless due to a board design error
 #define HAS_OTG_USB_HOST_SUPPORT                  // USB Flash Drive support
 #define M5_EXTENDER                               // The M5 extender is attached
 
@@ -106,6 +106,7 @@
 // Pins on the extender
 //
 #if ENABLED(M5_EXTENDER)
+  #define USES_DIAG_JUMPERS                       // DIAG jumpers work on M5 extender
   #ifndef X2_STOP_PIN
     #define X2_STOP_PIN                     PI4   // M5 M1_STOP
   #endif