viafb: kill viafb_load_crtc_timing

This patch replaces calls to viafb_load_crtc_timing with the code.
This should make it easier to fix the oddity that in the modetable
the blank and sync end entries contain the length and we need to add
the start values to get those to be written to the hardware.

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