feat(rmm-eac4): modify RSI_ATTESTATION_TOKEN commands

Modifies RSI_ATTESTATION_TOKEN_INIT and
RSI_ATTESTATION_TOKEN_CONTINUE commands as per
RMM Specification 1.0-eac4.
Number of 4K pages allocated for attestation
buffer is defined by RMM_ATTEST_BUFFER_PAGES
in CommonConfigs.cmake and set to 1 by default.

Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
Change-Id: Icda7f26e291a19b143ae14a291c03cc7bda0e076
diff --git a/lib/realm/include/rec.h b/lib/realm/include/rec.h
index d39819d..49c516d 100644
--- a/lib/realm/include/rec.h
+++ b/lib/realm/include/rec.h
@@ -131,6 +131,9 @@
 
 	/* Pointer to attestation-related data */
 	struct rec_attest_data *attest_data;
+
+	/* Address of the attestation token buffer */
+	uintptr_t cca_token_buf;
 };
 
 struct rec {