scsi: ufs: Configure Vccq/Vccq2 with supplied load in LPM

Configure the ufs vccq/vccq2 regulator with supplied load instead
of fixed load in LPM mode.

To configure regulator in LPM mode, on some targets explicit load
(<10mA or <30mA) has to be supplied. On other targets, clients need
to set load exactly as 0. On second category of targets, any load
value other than 0, pushes the regulator to NMP mode.

Adding support for reading load value for Vccq regulator from
device tree. If this property is not present, the regulator would
be set with default load (1mA).

Change-Id: Ifef004f2ea4d3612bc8410b82011fbcfc293ea6f
Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>