[bsp][stm32][f769-disco]Fix the problem of indentation.

Signed-off-by: Willian Chan <chentingwei@rt-thread.com>

bsp/stm32/stm32f769-st-disco/rtconfig.py

@@ -16,14 +16,14 @@ if os.getenv('RTT_ROOT'):
 # cross_tool provides the cross compiler
 # EXEC_PATH is the compiler execute path, for example, CodeSourcery, Keil MDK, IAR
 if  CROSS_TOOL == 'gcc':
-    PLATFORM 	= 'gcc'
-    EXEC_PATH 	= r'C:\Users\XXYYZZ'
+    PLATFORM    = 'gcc'
+    EXEC_PATH   = r'C:\Users\XXYYZZ'
 elif CROSS_TOOL == 'keil':
-    PLATFORM 	= 'armcc'
-    EXEC_PATH 	= r'C:/Keil_v5'
+    PLATFORM    = 'armcc'
+    EXEC_PATH   = r'C:/Keil_v5'
 elif CROSS_TOOL == 'iar':
-	PLATFORM 	= 'iar'
-	EXEC_PATH 	= r'C:/Program Files (x86)/IAR Systems/Embedded Workbench 8.0'
+    PLATFORM    = 'iar'
+    EXEC_PATH   = r'C:/Program Files (x86)/IAR Systems/Embedded Workbench 8.0'
 
 if os.getenv('RTT_EXEC_PATH'):
     EXEC_PATH = os.getenv('RTT_EXEC_PATH')