lib/cmsis: revert to previous version, to avoid new compilation errors.

See ARM-software/CMSIS_5#1397, which is not yet fixed in cmsis

Author: dhalbert

lib/cmsis/inc/cachel1_armv7.h

@@ -123,10 +123,6 @@
   #ifndef   __RESTRICT
     #define __RESTRICT                             __restrict
   #endif
-  #ifndef   __COMPILER_BARRIER
-    #warning No compiler specific solution for __COMPILER_BARRIER. __COMPILER_BARRIER is ignored.
-    #define __COMPILER_BARRIER()                   (void)0
-  #endif
 
 
 /*
@@ -196,10 +192,6 @@
     #warning No compiler specific solution for __RESTRICT. __RESTRICT is ignored.
     #define __RESTRICT
   #endif
-  #ifndef   __COMPILER_BARRIER
-    #warning No compiler specific solution for __COMPILER_BARRIER. __COMPILER_BARRIER is ignored.
-    #define __COMPILER_BARRIER()                   (void)0
-  #endif
 
 
 /*
@@ -268,10 +260,6 @@
     #warning No compiler specific solution for __RESTRICT. __RESTRICT is ignored.
     #define __RESTRICT
   #endif
-  #ifndef   __COMPILER_BARRIER
-    #warning No compiler specific solution for __COMPILER_BARRIER. __COMPILER_BARRIER is ignored.
-    #define __COMPILER_BARRIER()                   (void)0
-  #endif
 
 
 #else