Fix pivot offset calculation for negative incx

Author: martin-frbg

lapack/laswp/generic/laswp_k_4.c

@@ -65,10 +65,9 @@ int CNAME(BLASLONG n, BLASLONG k1, BLASLONG k2, FLOAT dummy1, FLOAT *a, BLASLONG
   a--;
   k1 --;
 
-#ifndef MINUS
  ipiv += k1;
-#else
-  ipiv -= (k2 - 1) * incx;
+#ifdef MINUS
+  ipiv -= (k2 - k1 - 1) * incx;
 #endif
 
   if (n  <= 0) return 0;