chore(rme): add make rule for SPD=spmd

ENABLE_RME is set then SPD must either be spmd or it should not be set.
Add a rule to assert this.

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: I0556e7b0e55b04c3a8e4c20c991fbbc30486570c
1 file changed