input: qcom-hv-haptics: add support to operate from non-HBoost regulator

By default, haptics module is supplied from HBoost module and it
talks to HBoost module in hardware to get an appropriate operating
voltage. Haptics module can also be supplied from non-HBoost regulator
and it requires software to request the voltage.

Add support to operate haptics under a fixed voltage from a non-HBoost
regulator. Make the following modifications:
  1) Set voltage and enable the regulator before enabling the play.
  2) Force VREG_RDY signal in haptics module before enabling the play.
  3) Scale the DIRECT_PLAY amplitude to achieve appropriate output
     voltage in constant playing.
  4) Scale the DIRECT_PLAY amplitude instead of Vmax setting for
     gain setting in constant playing.
  5) Adjust the LRA impedance detectability according to the regulator
     output voltage.

Change-Id: If832b6512d7641ad3d271bb68f4bdb7dbb90a5c5
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>