ring-buffer: remove useless warn on check

A check if "write > BUF_PAGE_SIZE" is done right after a

	if (write > BUF_PAGE_SIZE)
		return ...;

Thus the check is actually testing the compiler and not the
kernel. This is useless, remove it.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/ring_buffer.c

@@ -1334,9 +1334,6 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
 
 	/* We reserved something on the buffer */
 
-	if (RB_WARN_ON(cpu_buffer, write > BUF_PAGE_SIZE))
-		return NULL;
-
 	event = __rb_page_index(tail_page, tail);
 	rb_update_event(event, type, length);