feat(drtm): add Event Log driver support for DRTM

Added Event Log driver support for DRTM. This driver
is responsible for the doing the hash measurement of
various DRTM components as per [1], and putting these
measurements in the Event Log buffer.

[1]: https://developer.arm.com/documentation/den0113/a, section 3.16

Change-Id: I9892c313cf6640b82e261738116fe00f7975ee12
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
5 files changed