wwan_hwsim: fix possible memory leak in wwan_hwsim_dev_new()

wwan_hwsim: fix possible memory leak in wwan_hwsim_dev_new()

Inject fault while probing module, if device_register() fails,
but the refcount of kobject is not decreased to 0, the name
allocated in dev_set_name() is leaked. Fix this by calling
put_device(), so that name can be freed in callback function
kobject_cleanup().

unreferenced object 0xffff88810152ad20 (size 8):
  comm "modprobe", pid 252, jiffies 4294849206 (age 22.713s)
  hex dump (first 8 bytes):
    68 77 73 69 6d 30 00 ff                          hwsim0..
  backtrace:
    [<000000009c3504ed>] __kmalloc_node_track_caller+0x44/0x1b0
    [<00000000c0228a5e>] kvasprintf+0xb5/0x140
    [<00000000cff8c21f>] kvasprintf_const+0x55/0x180
    [<0000000055a1e073>] kobject_set_name_vargs+0x56/0x150
    [<000000000a80b139>] dev_set_name+0xab/0xe0

Fixes: f36a111a74e7 ("wwan_hwsim: WWAN device simulator")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Acked-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Link: https://lore.kernel.org/r/20221018131607.1901641-1-yangyingliang@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>