fbdev: fix 1bpp logo for unusual width

This check is needed in the case where the width of the framebuffer
is not a multiple of 8 pixels. For example, LEGO MINDSTORMS EV3 has
a 178x128 1bpp display.

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>