futex: Remove unneeded gotos

Get rid of gotos that do not contain any cleanup. These were not removed in
commit 9180bd46 ("futex: Remove put_futex_key()").

Signed-off-by: Jangwoong Kim <6812skiii@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201230122953.10473-1-6812skiii@gmail.com