power: qpnp-qnovo5: Add standalone class param

The "standalone" class parameter disables the charge pump if it is in
operation when a non-zero value is written to it via the QNOVO_VOTER
voter. This vote is revoked when 0 is written to it. Reading the
"standalone" parameter returns the effective value of the CP_DISABLED
votable, i.e. it shows whether the charge pump has been disabled by any
voter, not just QNOVO_VOTER.

Change-Id: I5d8fcd5b939ad5166548d041ba527e254f7026eb
Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>