nfc: virtual_ncidev: Fix memory leak in virtual_nci_send()

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

nfc: virtual_ncidev: Fix memory leak in virtual_nci_send()

skb should be free in virtual_nci_send(), otherwise kmemleak will report

memleak.

Steps for reproduction (simulated in qemu):

cd tools/testing/selftests/nci

make

./nci_dev

BUG: memory leak

unreferenced object 0xffff888107588000 (size 208):

comm "nci_dev", pid 206, jiffies 4294945376 (age 368.248s)

hex dump (first 32 bytes):

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................

backtrace:

[<000000008d94c8fd>] __alloc_skb+0x1da/0x290

[<00000000278bc7f8>] nci_send_cmd+0xa3/0x350

[<0000000081256a22>] nci_reset_req+0x6b/0xa0

[<000000009e721112>] __nci_request+0x90/0x250

[<000000005d556e59>] nci_dev_up+0x217/0x5b0

[<00000000e618ce62>] nfc_dev_up+0x114/0x220

[<00000000981e226b>] nfc_genl_dev_up+0x94/0xe0

[<000000009bb03517>] genl_family_rcv_msg_doit.isra.14+0x228/0x2d0

[<00000000b7f8c101>] genl_rcv_msg+0x35c/0x640

[<00000000c94075ff>] netlink_rcv_skb+0x11e/0x350

[<00000000440cfb1e>] genl_rcv+0x24/0x40

[<0000000062593b40>] netlink_unicast+0x43f/0x640

[<000000001d0b13cc>] netlink_sendmsg+0x73a/0xbf0

[<000000003272487f>] __sys_sendto+0x324/0x370

[<00000000ef9f1747>] __x64_sys_sendto+0xdd/0x1b0

[<000000001e437841>] do_syscall_64+0x3f/0x90