wwan_hwsim: fix possible memory leak in wwan_hwsim_dev_new()

In the Linux kernel, the following vulnerability has been resolved:

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