ECDSA: Add mbedtls_ecdsa_can_do

programs/test/benchmark.c

diff --git a/programs/test/benchmark.c b/programs/test/benchmark.c
index 0d4837f..a53851a 100755
--- a/programs/test/benchmark.c
+++ b/programs/test/benchmark.c
@@ -835,6 +835,9 @@
              curve_info->grp_id != MBEDTLS_ECP_DP_NONE;
              curve_info++ )
         {
+            if( mbedtls_ecdsa_can_do( curve_info->grp_id ) == 0 )
+                continue;
+
             mbedtls_ecdsa_init( &ecdsa );
 
             if( mbedtls_ecdsa_genkey( &ecdsa, curve_info->grp_id, myrand, NULL ) != 0 )
@@ -854,6 +857,9 @@
              curve_info->grp_id != MBEDTLS_ECP_DP_NONE;
              curve_info++ )
         {
+            if( mbedtls_ecdsa_can_do( curve_info->grp_id ) == 0 )
+                continue;
+
             mbedtls_ecdsa_init( &ecdsa );
 
             if( mbedtls_ecdsa_genkey( &ecdsa, curve_info->grp_id, myrand, NULL ) != 0 ||