Biqu SKR 1.1 => BigTree SKR 1.1 (#14514)

Marlin/src/core/boards.h

 #define BOARD_COHESION3D_MINI         2011  // Cohesion3D Mini
 #define BOARD_SMOOTHIEBOARD           2012  // Smoothieboard
 #define BOARD_AZTEEG_X5_MINI_WIFI     2013  // Azteeg X5 Mini Wifi (Power outputs: Hotend0, Bed, Fan)
-#define BOARD_BIQU_SKR_V1_1           2014  // BIQU SKR_V1.1 (Power outputs: Hotend0,Hotend1, Fan, Bed)
+#define BOARD_BIGTREE_SKR_V1_1        2014  // BIGTREE SKR_V1.1 (Power outputs: Hotend0,Hotend1, Fan, Bed)
 #define BOARD_BIQU_B300_V1_0          2015  // BIQU B300_V1.0 (Power outputs: Hotend0, Fan, Bed, SPI Driver)
 #define BOARD_BIGTREE_SKR_V1_3        2016  // BIGTREE SKR_V1.3 (Power outputs: Hotend0, Hotend1, Fan, Bed)
 #define BOARD_AZTEEG_X5_MINI          2017  // Azteeg X5 Mini (Power outputs: Hotend0, Bed, Fan)

Marlin/src/pins/pins.h

   #include "pins_COHESION3D_MINI.h"     // LPC1769                                    env:LPC1769
 #elif MB(SMOOTHIEBOARD)
   #include "pins_SMOOTHIEBOARD.h"       // LPC1769                                    env:LPC1769
-#elif MB(BIQU_SKR_V1_1)
-  #include "pins_BIQU_SKR_V1.1.h"       // LPC1768                                    env:LPC1768
+#elif MB(BIGTREE_SKR_V1_1)
+  #include "pins_BIGTREE_SKR_V1.1.h"    // LPC1768                                    env:LPC1768
 #elif MB(BIQU_B300_V1_0)
   #include "pins_BIQU_B300_V1.0.h"      // LPC1768                                    env:LPC1768
 #elif MB(BIGTREE_SKR_V1_3)

Marlin/src/pins/pins_BIQU_SKR_V1.1.h → Marlin/src/pins/pins_BIGTREE_SKR_V1.1.h

 #endif
 
 #ifndef BOARD_NAME
-  #define BOARD_NAME "BIQU SKR V1.1"
+  #define BOARD_NAME "BIGTREE SKR V1.1"
 #endif
 
 //