fbdev: asiliantfb: unsigned subtraction not less than 0

index 1fd22f4..de6c408 100644
@@ -140,7 +140,7 @@ static void asiliant_calc_dclk2(u32 *ppixclock, u8 *dclk2_m, u8 *dclk2_n, u8 *dc
 
 		/* 3 <= m <= 257 */
 		if (m >= 3 && m <= 257) {
-			unsigned new_error = ((Ftarget * n) - (Fref * m)) >= 0 ?
+			unsigned new_error = Ftarget * n >= Fref * m ?
 					       ((Ftarget * n) - (Fref * m)) : ((Fref * m) - (Ftarget * n));
 			if (new_error < best_error) {
 				best_n = n;

@@ -152,7 +152,7 @@ static void asiliant_calc_dclk2(u32 *ppixclock, u8 *dclk2_m, u8 *dclk2_n, u8 *dc
 		else if (m <= 1028) {
 			/* remember there are still only 8-bits of precision in m, so
 			 * avoid over-optimistic error calculations */
-			unsigned new_error = ((Ftarget * n) - (Fref * (m & ~3))) >= 0 ?
+			unsigned new_error = Ftarget * n >= Fref * (m & ~3) ?
 					       ((Ftarget * n) - (Fref * (m & ~3))) : ((Fref * (m & ~3)) - (Ftarget * n));
 			if (new_error < best_error) {
 				best_n = n;