power: qpnp-qg: Minor updates to SOC scaling features

1. Do not use module_param for FVSS dynamic parameters.
2. Ability to runtime enable/disable SOC scaling features.
3. Debug logging only if the feature is enabled.

Change-Id: I5da1cf368d523768d0b267b314394612934a6202
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>