viafb: eliminate viafb_get_pixclock

As there is only one user we can just insert the formula where
needed. Avoids one lookup in the modetable and
viafb_fill_var_timing_info does no longer depend on the modetable.

Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

diff --cc drivers/video/via/hw.c
Simple merge

diff --cc drivers/video/via/hw.h
Simple merge

diff --cc drivers/video/via/share.h
Simple merge