drm/i915/guc/slpc: Restore efficient freq earlier

This should be done before the soft min/max frequencies are restored.
When we disable the "Ignore efficient frequency" flag, GuC does not
actually bring the requested freq down to RPn.

Specifically, this scenario-

- ignore efficient freq set to true
- reduce min to RPn (from efficient)
- suspend
- resume (includes GuC load, restore soft min/max, restore efficient freq)
- validate min freq has been resored to RPn

This will fail if we didn't first restore(disable, in this case) efficient
freq flag before setting the soft min frequency.

v2: Bring the min freq down to RPn when we disable efficient freq (Rodrigo)
Also made the change to set the min softlimit to RPn at init. Otherwise, we
were storing RPe there.

Link: https://gitlab.freedesktop.org/drm/intel/-/issues/8736


Fixes: 55f9720d ("drm/i915/guc/slpc: Provide sysfs for efficient freq")
Fixes: 95ccf312 ("drm/i915/guc/slpc: Allow SLPC to use efficient frequency")
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230726010044.3280402-1-vinay.belgaumkar@intel.com