ci: drop redundant configuration

The l1 build configuration fvp-default,fvp-spm,nil is
redundant, given this is also in l1:
fvp-default,fvp-spm,fvp-default,nil.

The later adds build of tf-a-tests to the later.

Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: I0ec5270c973c027d33395ec866e3b830c35933da
1 file changed