[script] update doc and avoid modify README.MD when updating arch files

openfpga_flow/vpr_arch/Makefile

@@ -17,7 +17,7 @@ help:
 
 v1p1_to_v1p2:
 # This commands will update all the architecture file from v1.1 to v1.2
-	for f in `ls .`; do ${PYTHON_EXEC} ${ARCH_UPDATER} --input_file $${f} --output_file $${f}; done;
+	for f in `ls *.xml`; do ${PYTHON_EXEC} ${ARCH_UPDATER} --input_file $${f} --output_file $${f}; done;
 
 # Functions to extract comments from Makefiles
 define COMMENT_EXTRACT

openfpga_flow/vpr_arch/README.md

@@ -29,3 +29,11 @@ Please reveal the following architecture features in the names to help quickly s
 - GlobalTile<Int>Clk: How many clocks are defined through global ports from physical tiles. <Int> is the number of clocks 
 
 Other features are used in naming should be listed here.
+
+# Update architecture files in batch
+
+## From v1.1 to v1.2
+
+```
+make v1p1_to_v1p2
+```