mfd: Disable more pulls on WM8994

Disable more pulls by default on WM8994 for a small current saving. Since
some designs do leave SPKMODE floating provide platform data to allow that
to be left enabled.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>