MFD: twl6040: function to query the vibra status for clients

MFD: twl6040: function to query the vibra status for clients

If the client only interested, if any of the vibra channels enabled, or
if any of the channels are set to receive audio data via PDM.

This function targets mainly the vibra driver, so it can check if it is
allowed to execute effects ot not.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Samuel Ortiz <samuel.ortiz@intel.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>