From: James Simmons <jsimmons@infradead.org>

This fixes the bugs that where in mode switch via stty.

The problem was we couldn't set the mode just by using the x and y
resolution.  We use modedb to fill in the rest.  There also was a bug that
allowed you to change the console resolution for drivers with fixed
resolutions.  This would mess up your display.  Now that is fixed.