feat(memory share): support sending fragmented messages.

Updates `memory_init_and_send` to allow sending memory share messages
across multiple fragments.
Tests for this functionality will be added in the next commit.

Change-Id: I6a47735415a8fed1d15322499f1d08cc3e1fd6a2
Signed-off-by: Karl Meakin <karl.meakin@arm.com>
diff --git a/tftf/tests/misc_tests/test_invalid_access.c b/tftf/tests/misc_tests/test_invalid_access.c
index 353162b..b05d694 100644
--- a/tftf/tests/misc_tests/test_invalid_access.c
+++ b/tftf/tests/misc_tests/test_invalid_access.c
@@ -306,8 +306,7 @@
 
 	GET_TFTF_MAILBOX(mb);
 
-	handle = memory_init_and_send((struct ffa_memory_region *)mb.send,
-				      PAGE_SIZE, SENDER, &receiver, 1,
+	handle = memory_init_and_send(mb.send, PAGE_SIZE, SENDER, &receiver, 1,
 				      constituents, constituents_count,
 				      FFA_MEM_SHARE_SMC32, &ret);