cleanup: fix code smell knownConditionTrueFalse

Inner 'p->stresslevel>=4' will always be true. Thus checking for
count_stressed is redundant.

src/libespeak-ng/intonation.c

 	p = &phoneme_list[0];
 	for (ix = 0; ix < n_phoneme_list; ix++, p++) {
 		if ((p->type == phVOWEL) && (p->stresslevel >= 4)) {
-			if (count_stressed == 0)
-				final_stressed = ix;
-
-			if (p->stresslevel >= 4) {
-				final_stressed = ix;
-				count_stressed++;
-			}
+			final_stressed = ix;
+			count_stressed++;
 		}
 	}