[PATCH] mbxfb: Fix a chip bug? resulting in wrong pixclock

This is a workaround for what I think is a bug in the 2700G chip.

The PLL output frequency is adustable using 3 values (M, N and P.  See code
for formula).  The N value range is documented to be 1 to 7 but when it is set
to 1, the output frequency is lower than it should be (divided by 2), giving
unexpected results such as no sync on a CRT display.

This patch prevents N=1 when searching for the best value for the requested
pixclock.

Signed-off-by: Raphael Assenat <raph@8d.com>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>