pstore: Replace arguments for write_buf() API

As with the other API updates, this removes the long argument list in favor
of passing a single pstore recaord.

Signed-off-by: Kees Cook <keescook@chromium.org>
diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c
index 899d0ba..a5506ec 100644
--- a/fs/pstore/ftrace.c
+++ b/fs/pstore/ftrace.c
@@ -37,6 +37,12 @@ static void notrace pstore_ftrace_call(unsigned long ip,
 {
 	unsigned long flags;
 	struct pstore_ftrace_record rec = {};
+	struct pstore_record record = {
+		.type = PSTORE_TYPE_FTRACE,
+		.buf = (char *)&rec,
+		.size = sizeof(rec),
+		.psi = psinfo,
+	};
 
 	if (unlikely(oops_in_progress))
 		return;
@@ -47,8 +53,7 @@ static void notrace pstore_ftrace_call(unsigned long ip,
 	rec.parent_ip = parent_ip;
 	pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++);
 	pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
-	psinfo->write_buf(PSTORE_TYPE_FTRACE, 0, NULL, 0, (void *)&rec,
-			  0, sizeof(rec), psinfo);
+	psinfo->write_buf(&record);
 
 	local_irq_restore(flags);
 }