s3fb: updates

Move s3fb_get_tilemax to svgalib.c as svga_get_tilemax, because it reports
limitation of other code from svgalib (svga_settile, svga_tilecopy, ...)

Limit font width to 8 pixels in 4 bpp mode.

Signed-off-by: Ondrej Zajicek <santiago@crfreenet.org>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>