netdevsim: remove redundant variable ret

Return value directly from nsim_dev_reload_create()
instead of getting value from redundant variable ret.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Jinpeng Cui <cui.jinpeng2@zte.com.cn>
Link: https://lore.kernel.org/r/20220831154329.305372-1-cui.jinpeng2@zte.com.cn


Signed-off-by: Jakub Kicinski <kuba@kernel.org>