memory-layout/memory-operations: Fix swapRows call in pixels solution

The proposed solution for reversePic erroneously passes the height of the
image to the ancillary function that swaps rows. Updated to use width
instead.

Signed-off-by: Cosmin Popa <[email protected]>

chapters/memory-layout/memory-operations/drills/tasks/pixels/solution/pixels.c

@@ -34,7 +34,7 @@ void reverse_pic(struct picture *pic)
 {
 	for (int i = 0; i < pic->height / 2; ++i)
 		swap_rows(pic->pix_array[i], pic->pix_array[pic->height - 1 - i],
-				pic->height);
+				pic->width);
 }
 
 int main(void)