net: microchip: vcap api: Fix memory leaks in vcap_api_encode_rule_test()

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

net: microchip: vcap api: Fix memory leaks in vcap_api_encode_rule_test()

Commit a3c1e45156ad ("net: microchip: vcap: Fix use-after-free error in
kunit test") fixed the use-after-free error, but introduced below
memory leaks by removing necessary vcap_free_rule(), add it to fix it.

unreferenced object 0xffffff80ca58b700 (size 192):
  comm "kunit_try_catch", pid 1215, jiffies 4294898264
  hex dump (first 32 bytes):
    00 12 7a 00 05 00 00 00 0a 00 00 00 64 00 00 00  ..z.........d...
    00 00 00 00 00 00 00 00 00 04 0b cc 80 ff ff ff  ................
  backtrace (crc 9c09c3fe):
    [<0000000052a0be73>] kmemleak_alloc+0x34/0x40
    [<0000000043605459>] __kmalloc_cache_noprof+0x26c/0x2f4
    [<0000000040a01b8d>] vcap_alloc_rule+0x3cc/0x9c4
    [<000000003fe86110>] vcap_api_encode_rule_test+0x1ac/0x16b0
    [<00000000b3595fc4>] kunit_try_run_case+0x13c/0x3ac
    [<0000000010f5d2bf>] kunit_generic_run_threadfn_adapter+0x80/0xec
    [<00000000c5d82c9a>] kthread+0x2e8/0x374
    [<00000000f4287308>] ret_from_fork+0x10/0x20
unreferenced object 0xffffff80cc0b0400 (size 64):
  comm "kunit_try_catch", pid 1215, jiffies 4294898265
  hex dump (first 32 bytes):
    80 04 0b cc 80 ff ff ff 18 b7 58 ca 80 ff ff ff  ..........X.....
    39 00 00 00 02 00 00 00 06 05 04 03 02 01 ff ff  9...............
  backtrace (crc daf014e9):
    [<0000000052a0be73>] kmemleak_alloc+0x34/0x40
    [<0000000043605459…