update readme

components/libc/compilers/common/all/readme.md

@@ -1,6 +1,6 @@
 ## Attentions
 
-1. This folder is "common" for armlibc newlibc and dlib.
+1. This folder is "common" for all toolchains.
 
 2. If you want to add new `.c` files, please do not forget to fix SConscript file too. eg:
 

components/libc/compilers/common/excgcc/readme.md

@@ -1,3 +1,3 @@
 ## Attentions
 
-This folder is "common" for armlibc and dlib.
+This folder is "common" for toolchains excluding gcc.