Add media top-level directory for storage medium access components

Introduces the top-level media directory for components concerned
with accessing storage media using well-known formats. Reuses
external source code from TF-A where possible.

Signed-off-by: Julian Hall <julian.hall@arm.com>
Change-Id: I5fa2cb24aa33f019df5108e80ccd78f0170e4c0b
18 files changed