chore: use FVP_Base_Cortex-A710 over FVP_Base_Cortex-A710x4

The FVP_Base_Cortex-A710x4 FVP is no longer distributed, but the
FVP_Base_Cortex-A710 suffices for all of the tests that we need the
quad-core configuration for.

Change-Id: I4249d47785845191108503fab6dfca67b7239843
Signed-off-by: Chris Kay <chris.kay@arm.com>
3 files changed