vsock: remove unnecessary null check in vsock_getname()

The local variable 'vm_addr' is always not NULL, no need to check it.

Signed-off-by: Wang Liang <wangliang74@huawei.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://patch.msgid.link/20250725013808.337924-1-wangliang74@huawei.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>