drm/i915: Don't let update_psr function actually enable PSR.
drm/i915: Don't let update_psr function actually enable PSR.

Being more conservative by enabling PSR only on psr_enable function.

Reviewed-by: Vijay Purushothaman <c5f48811591ae9f9ebdbe7711f70c5199e72df29@intel.com>
Signed-off-by: Rodrigo Vivi <f714145d6ee82178e54021e0c168f56d17b53c9c@intel.com>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs