MFD: twl6040: Fix power on GPIO handling

Avoid requesting the audpwron gpio in case of ES1.0
revision.
In the past we requested the gpio, but we did not
free it up, since we made the check for the revision
later. This results later checks for gpio validity to
fail, leaving the gpio reserved (even after the driver
has been removed).

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>