Documentation: fix pm/intel_pstate build warning and wording

Fix documentation build warning and sentence wording:

Documentation/admin-guide/pm/intel_pstate.rst:568: WARNING: Unexpected indentation.

Fixes: f473bf39 ("cpufreq: intel_pstate: Allow raw energy performance preference value")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>