IntelSiliconPkg/Feature/SmmAccess/*: Fix incorrect Doxygen comment

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2436



Fixed some doxygen comment that does not follow correct doxygen format.
Updated some description of some functions.

Notes:
v1:
- Initial version of code change.
v2:
- Update some description of some functions.
v3:
- Update some description of some functions.
v4:
- Change "post" to "POST".
v5:
- Fixed typo of subject from "Doxcgen" to "Doxygen".

Cc: Michael Kubacki <michael.a.kubacki@intel.com>
Cc: Sai Chaganty <rangasai.v.chaganty@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Shenglei Zhang <shenglei.zhang@intel.com>
Signed-off-by: Marc Chen <marc.w.chen@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Sai Chaganty <rangasai.v.chaganty@intel.com>