fix: remove superfluous BEFORE_COLON in x509_crl.c

BEFORE_COLON and BC defines with the accompanying comment are only
required in x509_crt and x509_csr, but not used in x509_crl.c.

Signed-off-by: Stefan Gloor <stefan.gloor@siemens.com>
diff --git a/library/x509_crl.c b/library/x509_crl.c
index e67fde7..bc4fdbb 100644
--- a/library/x509_crl.c
+++ b/library/x509_crl.c
@@ -583,11 +583,6 @@
 
 #if !defined(MBEDTLS_X509_REMOVE_INFO)
 /*
- * Return an informational string about the certificate.
- */
-#define BEFORE_COLON    14
-#define BC              "14"
-/*
  * Return an informational string about the CRL.
  */
 int mbedtls_x509_crl_info(char *buf, size_t size, const char *prefix,