build(tbbr): drive cert_create changes for cca CoT

build(tbbr): drive cert_create changes for cca CoT

The build system needs to drive the cert_create tool in a slightly
different manner when using the cca chain of trust.

- It needs to pass it the plat, core_swd, and swd ROT key files.

- It must now generate the cca, core_swd, and plat key certificates,
and exclude the non-relevant certificates.

Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>
Change-Id: I5759bfaf06913f86b47c7d04c897773bba16a807