tracing: Drop unneeded assignment in ring_buffer_resize()

Since commit 0a1754b2a9 ("ring-buffer: Return 0 on success from
ring_buffer_resize()"), computing the size is not needed anymore.

Drop unneeded assignment in ring_buffer_resize().

Link: https://lkml.kernel.org/r/20201214084503.3079-1-lukas.bulwahn@gmail.com

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/ring_buffer.c

@@ -1974,8 +1974,6 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
 	if (nr_pages < 2)
 		nr_pages = 2;
 
-	size = nr_pages * BUF_PAGE_SIZE;
-
 	/* prevent another thread from changing buffer sizes */
 	mutex_lock(&buffer->mutex);