Build: Convert secure_fw dir to modern cmake

Rewrite cmake files inside the secure_fw directory. Removed generated
files as they are now generated into the build tree. Alter header
includes where include paths have changed.

WARNING: This change will not build in isolation, it requires _all_
other cmake changes to successfully build. It is split out only for
clarity of changes.

Change-Id: Ib1b13c9b69f2fcb1ff354ed6b5e5b717a207e3b8
Signed-off-by: Raef Coles <raef.coles@arm.com>
30 files changed