Switch to the new code style

Signed-off-by: David Horstmann <david.horstmann@arm.com>
diff --git a/library/aesni.c b/library/aesni.c
index 87d818a..54a3145 100644
--- a/library/aesni.c
+++ b/library/aesni.c
@@ -28,7 +28,8 @@
 
 #if defined(__has_feature)
 #if __has_feature(memory_sanitizer)
-#warning "MBEDTLS_AESNI_C is known to cause spurious error reports with some memory sanitizers as they do not understand the assembly code."
+#warning \
+    "MBEDTLS_AESNI_C is known to cause spurious error reports with some memory sanitizers as they do not understand the assembly code."
 #endif
 #endif