platform/x86/amd/pmf: Fix memory leak in amd_pmf_get_pb_data()

amd_pmf_get_pb_data() will allocate memory for the policy buffer,
but does not free it if copy_from_user() fails. This leads to a memory
leak.

Fixes: 10817f28

 ("platform/x86/amd/pmf: Add capability to sideload of policy binary")
Reviewed-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Signed-off-by: Cong Liu <liucong2@kylinos.cn>
Link: https://lore.kernel.org/r/20240124012939.6550-1-liucong2@kylinos.cn


Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>