ci(coverity): exclude LX2160A cert_create sources from Coverity

These source files are used only for the cert_create tools, and are
therefore not covered by Coverity.

Signed-off-by: Chris Kay <chris.kay@arm.com>
Change-Id: Iaf3d66fd6ea3dd3e45c7a3edf68b69130642f808
1 file changed