mfd: qcom-rpm: Expose sleep state resources to clients

Resources exposed from the RPM have an "active state" that is used during
normal operations and a "sleep state" that is used for HW assisted sleep
modes. Expose this in the api to let client drivers set the "sleep
state" as well.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
regulator: qcom-rpm: Implement RPM assisted disable

Some regulators are used to power e.g. PLLs that clocks the core we're
running on, so we can't turn them off directly; but we do want them off
when the core is powered down. To handle this the Qualcomm SoC provides
a means to specify a "sleep state" for RPM resources that can be
triggered by the hardware when the cores are brought down.

Resources of this type should be considered always-on while the CPU(s)
are running and we can utilize the "sleep state" functionality to defer
disabling them until the CPU(s) go to sleep, if not used by other
peripherals at that time.

Other properties are kept in sync between the states, so that if the
CPU(s) go to sleep with a particular regulator still enabled there will
be no change.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
regulator: qcom-rpm: Add pm8921_ln_ldo regulator type

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>