kms_flip: Fix use of fb_width for PAN subtests

kms_flip: Fix use of fb_width for PAN subtests

We need to be careful to remember that fb-width is not always the same
as hdisplay, since for panning we allocate a larger framebuffer. So fix
up the printfs to use hdisplay/vsisplay since that should be uniform
across the array.

Regression from
commit 919d68901187fa797a9b648fcf87c838fae22fa3
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu Aug 29 15:33:53 2013 +0100

    kms_flips: Operate on an array of crtc

Buzilla: https://bugs.freedesktop.org/show_bug.cgi?id=68832
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>