drivers/video/ssd1307fb.c: fix bit order bug in the byte translation function

This was leading to a strange behaviour when using the fbcon driver on
top of this one: the letters were in the right order, but each letter
had a vertical symmetry.

This was because the addressing was right for the byte, but the
addressing of each individual bit was inverted.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Brian Lilly <brian@crystalfontz.com>
Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Thomas Petazzoni <thomas@free-electrons.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>