Make the firmware speedup work for the 5000c as well as the original
xc5000.  This cuts firmware load time in half.

Thanks to John Casey at Hauppauge for loaning me a board for testing.
Signed-off-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>