feat(lib): introduce Hob creation library

According to Platform Initialization (PI) Specification [1] and
discussion on edk2 mailing list [2],
StandaloneMm shouldn't create Hob but it should be passed from TF-A.
IOW, TF-A should pass boot information via HOB list to initialise
StandaloneMm properly.

And this HOB lists could be delivered via
    - SPM_MM: Transfer List according to the firmware handoff spec[3]

    - FF-A v1.1 >= : FF-A boot protocol.

This patch introduces a TF-A HOB creation library and
some of definitions which StandaloneMm requires to boot.

Link: https://uefi.org/sites/default/files/resources/PI_Spec_1_6.pdf [1]
Link: https://edk2.groups.io/g/devel/topic/103675962#114283 [2]
Link: https://github.com/FirmwareHandoff/firmware_handoff [3]
Signed-off-by: Levi Yun <yeoreum.yun@arm.com>
Change-Id: I5e0838adce487110206998a8b79bc3adca922cec
diff --git a/docs/license.rst b/docs/license.rst
index 22d0e06..e35b9bb 100644
--- a/docs/license.rst
+++ b/docs/license.rst
@@ -116,6 +116,8 @@
    These files are:
 
    -  ``lib/hob/hob.c``
+   -  ``include/lib/hob/mmram.h``
+   -  ``include/lib/hob/mpinfo.h``
 
 .. _FreeBSD: http://www.freebsd.org
 .. _Linux MIT license: https://raw.githubusercontent.com/torvalds/linux/master/LICENSES/preferred/MIT