fix(rss): remove dependency on attestation header

Platform must define the maximum size of the message
over MHU.

Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Change-Id: I91a6c132c946f4465178910b8ea83544f562e837

drivers/arm/rss/rss_comms_protocol_embed.h

@@ -10,21 +10,11 @@
 
 #include <cdefs.h>
 
-#include <initial_attestation.h>
 #include <psa/client.h>
 
 #include <platform_def.h>
 
-/*
- * In the current implementation the RoT Service request that requires the
- * biggest message buffer is the RSS_ATTEST_GET_TOKEN. The maximum required
- * buffer size is calculated based on the platform-specific needs of
- * this request.
- */
-#ifndef RSS_COMMS_PAYLOAD_MAX_SIZE
-#define RSS_COMMS_PAYLOAD_MAX_SIZE	(PSA_INITIAL_ATTEST_CHALLENGE_SIZE_64 \
-					 + PLAT_ATTEST_TOKEN_MAX_SIZE)
-#endif
+
 
 struct __packed rss_embed_msg_t {
 	psa_handle_t handle;