ztrmv_L.c: no longer need a 4kB buffer

Fix #786

driver/level2/ztrmv_L.c

@@ -56,7 +56,7 @@ int CNAME(BLASLONG m, FLOAT *a, BLASLONG lda, FLOAT *b, BLASLONG incb, FLOAT *bu
 
   if (incb != 1) {
     B = buffer;
-    gemvbuffer = (FLOAT *)(((BLASLONG)buffer + m * sizeof(FLOAT) * 2 + 4095) & ~4095);
+    gemvbuffer = (FLOAT *)(((BLASLONG)buffer + m * sizeof(FLOAT) * 2 + 15) & ~15);
     COPY_K(m, b, incb, buffer, 1);
   }