fix(rse): include lib-psa to resolve build

Unless platforms include lib/psa into platform specific makefile the
rse_comms throws build error on its own:
  CC      drivers/arm/rse/rse_comms_protocol.c
drivers/arm/rse/rse_comms.c:13:10: fatal error: psa/client.h: No such file or directory
   13 | #include <psa/client.h>

So add PLAT_INCLUDES entry to include the lib/psa to rse_comms.mk.

Signed-off-by: Vivek Gautam <vivek.gautam@arm.com>
Change-Id: I4cbcbbaf20285990239d605f0b3b3dc92bea61e6
diff --git a/drivers/arm/rse/rse_comms.mk b/drivers/arm/rse/rse_comms.mk
index a1abc6a..3b87fe2 100644
--- a/drivers/arm/rse/rse_comms.mk
+++ b/drivers/arm/rse/rse_comms.mk
@@ -31,4 +31,5 @@
 endif
 
 PLAT_INCLUDES		+=	-Idrivers/arm/rse		\
-				-Idrivers/arm/mhu
+				-Idrivers/arm/mhu		\
+				-Iinclude/lib/psa