fix check for no-longer-used macro

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/constant_time_impl.h b/library/constant_time_impl.h
index f8f6bb1..c9e6a83 100644
--- a/library/constant_time_impl.h
+++ b/library/constant_time_impl.h
@@ -41,7 +41,7 @@
 
 /* armcc5 --gnu defines __GNUC__ but doesn't support GNU's extended asm */
 #if defined(MBEDTLS_HAVE_ASM) && defined(__GNUC__) && (!defined(__ARMCC_VERSION) || \
-    __ARMCC_VERSION >= 6000000) && !defined(MBEDTLS_CT_NO_ASM)
+    __ARMCC_VERSION >= 6000000)
 #define MBEDTLS_CT_ASM
 #if (defined(__arm__) || defined(__thumb__) || defined(__thumb2__))
 #define MBEDTLS_CT_ARM_ASM