TinyCrypt PK parse: Remove MBEDTLS_PK_ECDSA during pubkey parsing

The PK type MBEDTLS_PK_ECDSA is never returned from
`mbedtls_pk_info_from_type()`. Instead, EC keys either
are identified as MBEDTLS_PK_ECKEY_DH (in case they
must only be used for ECDHE) or MBEDTLS_PK_ECKEY (in
case they can be used for any algorithm).
diff --git a/library/pkparse.c b/library/pkparse.c
index 2df391d..713ee92 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -716,7 +716,7 @@
         return( ret );
 
 #if defined(MBEDTLS_USE_TINYCRYPT)
-    if( pk_alg == MBEDTLS_PK_ECDSA )
+    if( pk_alg == MBEDTLS_PK_ECKEY )
     {
         ret = pk_get_ueccpubkey( p, end, (uint8_t*) pk->pk_ctx );
     } else
@@ -1204,7 +1204,7 @@
     } else
 #endif /* MBEDTLS_RSA_C */
 #if defined(MBEDTLS_USE_TINYCRYPT)
-    if( pk_alg == MBEDTLS_PK_ECDSA)
+    if( pk_alg == MBEDTLS_PK_ECKEY )
     {
         if( ( ret = pk_use_ecparams( &params ) ) != 0 ||
             ( ret = pk_parse_key_sec1_der( mbedtls_uecc_pk( *pk ), p, len ) ) != 0)