Sanitize SPD include paths

Commit 09d40e0e

 ("Sanitise includes across codebase") modified the
include paths of the TSP includes but it didn't remove the include path
from the makefile or did the same for TLK. This patch does the remaining
work.

Change-Id: Iecee2e88fabcd06989d35568c3a4c1f4e7d93572
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>