cmac: preprocessor indentation fixes

Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10836)

include/openssl/cmac.h

@@ -18,11 +18,11 @@
 
 # ifndef OPENSSL_NO_CMAC
 
-#ifdef __cplusplus
+#  ifdef __cplusplus
 extern "C" {
-#endif
+#  endif
 
-# include <openssl/evp.h>
+#  include <openssl/evp.h>
 
 /* Opaque */
 typedef struct CMAC_CTX_st CMAC_CTX;
@@ -39,9 +39,9 @@ int CMAC_Update(CMAC_CTX *ctx, const void *data, size_t dlen);
 int CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen);
 int CMAC_resume(CMAC_CTX *ctx);
 
-#ifdef  __cplusplus
+#  ifdef  __cplusplus
 }
-#endif
+#  endif
 
 # endif
 #endif