Rename MBEDTLS_X509_INFO to !MBEDTLS_X509_REMOVE_INFO

The introduction of positive options to control the presence
of pre-existing functionality breaks the build for users of
handwritten configurations.

Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/include/mbedtls/x509_csr.h b/include/mbedtls/x509_csr.h
index b9e5b93..9f3cae2 100644
--- a/include/mbedtls/x509_csr.h
+++ b/include/mbedtls/x509_csr.h
@@ -121,7 +121,7 @@
 int mbedtls_x509_csr_parse_file( mbedtls_x509_csr *csr, const char *path );
 #endif /* MBEDTLS_FS_IO */
 
-#if defined(MBEDTLS_X509_INFO)
+#if !defined(MBEDTLS_X509_REMOVE_INFO)
 /**
  * \brief          Returns an informational string about the
  *                 CSR.