Remove parameters validation using ECP_VALIDATE_RET

Signed-off-by: Przemek Stekiel <przemyslaw.stekiel@mobica.com>
diff --git a/library/ecp.c b/library/ecp.c
index 71114cd..f39cb02 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -3363,10 +3363,6 @@
                        mbedtls_mpi *d, mbedtls_ecp_point *Q)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    ECP_VALIDATE_RET( key != NULL );
-    ECP_VALIDATE_RET( grp != NULL );
-    ECP_VALIDATE_RET( d != NULL );
-    ECP_VALIDATE_RET( Q != NULL );
 
     if( ( ret = mbedtls_ecp_group_copy( grp, &key->grp ) ) != 0 )
         return ret;