Merge tag 'regulator-v3.15-rc2' of git://

Pull regulator fixes from Mark Brown:
 "A couple of things here:

   - Fixes for pbias that didn't make it in during the merge window due
     to the driver coming in via MMC.  The conversion to use helpers is
     a fix as it implements list_voltage() which the main user (MMC)
     relies on for correct functioning.
   - Change the !REGULATOR stub for optional regulators to return an
     error rather than a dummy; this is more in keeping with the
     intended use of optional regulators and fixes some issues seen MMC
     where it got confused by a dummy being provided"

* tag 'regulator-v3.15-rc2' of git://
  regulator: core: Return error in get optional stub
  regulator: pbias: Convert to use regmap helper functions
  regulator: pbias: Fix is_enabled callback implementation