refactor: use Bash expressions to generate boot arguments

This change removes the final remaining macro used by the LAVA job
template files, which is `BOOT_ARGUMENTS`. In its place, use a simple
Bash expression which loops over the boot arguments and generates the
boot argument array entries.

Signed-off-by: Chris Kay <chris.kay@arm.com>
Change-Id: I688c819179ed0a4dea48d23a222acb1c3ef55625
3 files changed