refactor(fvp): remove certain tests

Certain Model configurations are not available
from FVP 11.26 remove those test configurations.

- FVP_Base_Cortex-A55x4+Cortex-A75x4
- FVP_Base_Cortex-A55x4+Cortex-A76x2

Remove those test configurations.

Change-Id: I7d15a17edca85907261e1f32055a23ba891016e0
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
(cherry picked from commit 74f45c6d2eaf3f7ee5489f9713bd7ca1feafdc0c)
8 files changed