Fixed MPI assembly for ARM when -O2 is used

GCC with -O2 or higher also needs to now about 'cc' in the clobber list.

ChangeLog

@@ -15,6 +15,9 @@ Changes
    * Moved all OID functionality to a separate module. RSA function
      prototypes for the RSA sign and verify functions changed as a result
 
+Bugfix
+   * Fix for MPI assembly for ARM
+
 = Version 1.2.6 released 2013-03-11
 Bugfix
    * Fixed memory leak in ssl_free() and ssl_reset() for active session

include/polarssl/bn_mul.h

@@ -606,7 +606,7 @@
          : "=m" (c),  "=m" (d), "=m" (s)        \
          : "m" (s), "m" (d), "m" (c), "m" (b)   \
          : "r0", "r1", "r2", "r3", "r4", "r5",  \
-           "r6", "r7", "r8", "r9"               \
+           "r6", "r7", "r8", "r9", "cc"         \
          );
 
 #else
@@ -640,7 +640,7 @@
          : "=m" (c),  "=m" (d), "=m" (s)        \
          : "m" (s), "m" (d), "m" (c), "m" (b)   \
          : "r0", "r1", "r2", "r3", "r4", "r5",  \
-           "r6", "r7"                           \
+           "r6", "r7", "cc"                     \
          );
 
 #endif /* Thumb */