gpio: cs5535-gpio: fix input direction

The cs5535-gpio driver's get() function was returning the output value.
This means that the GPIO pins would never work as an input, even if
configured as an input.

The driver should return the READ_BACK value, which is the sensed line
value.  To make that work when the direction is 'output', INPUT_ENABLE
needs to be set.

In addition, the driver was not disabling OUTPUT_ENABLE when the direction
is set to 'input'.  That would cause the GPIO to continue to drive the pin
if the direction was ever set to output.

This issue was noticed when attempting to use the gpiolib driver to read
an external input.  I had previously been using the char/cs5535-gpio
driver.

Signed-off-by: Ben Gardner <gardner.ben@gmail.com>
Acked-by: Andres Salomon <dilinger@collabora.co.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: <stable@kernel.org>		[2.6.33.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>