tc2: remove tc2 l2 boot tests

Based on dicussion from https://linaro.atlassian.net/browse/TFC-646
remoce TC2 tests from CI+2 checks.

Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
Change-Id: I3afd38096253f19f6b22f665ef7434c239bc746b