Dualcpu: Hotfix to fix unused ns_mailbox_spin_lock() error

ns_mailbox_spin_lock()/unlock() is unused without multi-core tests
and will break build in configression without tests.

Fix it by using TFM_MULTI_CORE_TEST to control build of them.

Change-Id: I859355607f6d67845e0945d980724276ea7d8dcb
Signed-off-by: David Hu <david.hu@arm.com>
1 file changed