tf-a-coverity.yaml: Fix the upload phase.

There were 2 errors:

 - We were trying to execute a git command outside of TF-A git repo.
   Fix this by 'cd'ing into TF-A git repo prior to that.

 - Environment variables were incorrectly quoted.

Also do some cosmetic changes along the way (adding empty lines,
small refactorings).

Change-Id: Ifc6986696a2ea0e465107d52cdf38ed3e276f5f6
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
1 file changed