Fixed E1_ENABLE pin for Ultimaker. This was wrong for the 1.5.4 and 1.5.3 PCB...

Fixed E1_ENABLE pin for Ultimaker. This was wrong for the 1.5.4 and 1.5.3 PCB (I cannot check the 1.5.6)

Marlin/pins.h

@@ -684,7 +684,7 @@
 
 #define E1_STEP_PIN         49
 #define E1_DIR_PIN          47
-#define E1_ENABLE_PIN       51
+#define E1_ENABLE_PIN       48
 
 #define SDPOWER            -1
 #define SDSS               53