M487: Fix ECP P + P operation

Engine doesn't support P + Q when P and Q are the same. Workaround by 2*P

Author: ccli8

connectivity/drivers/mbedtls/TARGET_NUVOTON/TARGET_M480/ecp/ecp_internal_alt.c

@@ -502,6 +502,11 @@ NU_STATIC int internal_run_eccop(const mbedtls_ecp_group *grp,
         return MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED;
     }
 
+    /* NOTE: Engine doesn't support P + Q when P and Q are the same. Workaround by 2*P */
+    if (mbedtls_ecp_point_cmp(P, Q) == 0) {
+        return internal_run_eccop(grp, R, NULL, P, NULL, NULL, ECCOP_POINT_DOUBLE);
+    }
+
     int ret;
     bool ecc_done;