wmtv: Fix calculation of bytes per line.

wmtv: Fix calculation of bytes per line.

Patch by Yann Vernier <yann@donkey.dyndns.org>.  From [1]:

   From: Malcolm Parsons <malcolm@ivywell.screaming.net>
   Subject: wmtv: incorrectly calculates bytes per line
   Date: Mon, 09 Apr 2001 21:15:52 +0100

   wmtv does not put the tv display in its window on my second head.
   According to bttv, wmtv is telling bttv that the display is:

   Display at ea800000 is 800 by 600, bytedepth 2, bpl 1600

   If I use xawtv, it correctly sets the bpl value:

   Display at ea800000 is 800 by 600, bytedepth 2, bpl 1664

   wmtv is probably incorrectly assuming width * bytedepth = bpl.

   From: Yann Vernier <yann@donkey.dyndns.org>
   Subject: wmtv: incorrectly calculates bytes per line
   Date: Sun, 15 Jul 2001 14:21:56 +0200

   Found the problem, at least this fixes it for me at 1600x1200.

[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=93439