tracing: Remove redundant initialization of variable ret

The variable ret is being initialized with a value that is never read,
it is being updated later on. The assignment is redundant and can be
removed.

Link: https://lkml.kernel.org/r/20210513115517.58178-1-colin.king@canonical.com



Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>