ci: enable USE_ROMLIB in Juno build config

Modified existing Juno build config to set USE_ROMLIB=1,
helping reduce image size for memory-constrained builds.

Change-Id: I1d01ca2ba4e3f8e69bd59d030bb566ace673c396
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
2 files changed