video: da8xx-fb: fixing timing off by one errors

The LCD controller represents some of the timing fields with a 0
in the register representing 1.  This was not taken into account
when these registers were being set.  Interestingly enough not
all of the LCDC controller timing registers implement this representation
so carefully went through the technical reference manual to only "fix"
the correct timings.

Signed-off-by: Darren Etheridge <detheridge@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>