Address Andres PR comments

Address Andres' comments in the PR

ChangeLog

@@ -38,8 +38,9 @@ Changes
      by Jean-Philippe Aumasson.
    * Add support for alternative implementation for ECDSA, controlled by new
      configuration flag MBEDTLS_ECDSA_ALT in config.h.
-     Alternative Ecdsa is supported for implementation of `mbedtls_ecdsa_sign`
-     and `mbedtls_ecdsa_verify`.
+     The following functions from the ECDSA module can be replaced
+     with an alternative implementation:
+     mbedtls_ecdsa_sign(), mbedtls_ecdsa_verify() and mbedtls_ecdsa_genkey().
 
 = mbed TLS 2.5.0 branch released 2017-05-17
 

library/ecdsa.c

@@ -37,9 +37,11 @@
 #include "mbedtls/asn1write.h"
 
 #include <string.h>
+
 #if defined(MBEDTLS_ECDSA_DETERMINISTIC)
 #include "mbedtls/hmac_drbg.h"
 #endif
+
 /*
  * Derive a suitable integer for group grp from a buffer of length len
  * SEC1 4.1.3 step 5 aka SEC1 4.1.4 step 3
@@ -314,6 +316,7 @@ static int ecdsa_signature_to_asn1( const mbedtls_mpi *r, const mbedtls_mpi *s,
 
     return( 0 );
 }
+
 /*
  * Compute and write signature
  */