x86/Documentation: Describe the Intel Hardware Feedback Interface

mainline inclusion
from mainline-5.18
commit 4a960e89
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I5DSOL



Intel_SIG: commit 4a960e89 x86/Documentation: Describe the Intel Hardware
Feedback Interface.
Backport for Intel HFI (Hardware Feedback Interface) support

-------------------------------------

Start a documentation file to describe the purpose and operation of Intel's
Hardware Feedback Interface. Describe how this interface is used in Linux
to relay performance and energy efficiency updates to userspace.

Reviewed-by: Len Brown <len.brown@intel.com>
Suggested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: yingbao jia <yingbao.jia@intel.com>
Signed-off-by: Jun Tian <jun.j.tian@intel.com>