remoteproc: qcom: Initialize and enable proxy and active regulators.

Certain regulators need voting by rproc on behalf of hexagon only during
restart operation but certain regulator need to be voted till hexagon
is up, these regulators are identified as proxy and active regulators
respectively. This patch provide interface to initialize, enable and
disable proxy and active regulators separately.

Signed-off-by: Avaneesh Kumar Dwivedi <akdwived@codeaurora.org>
[bjorn: dropped disable of proxy regulators from stop]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>