decnet: fix shutdown parameter checking
decnet: fix shutdown parameter checking

The allowed value of "how" is SHUT_RD/SHUT_WR/SHUT_RDWR (0/1/2),
rather than SHUTDOWN_MASK (3).

Signed-off-by: Xi Wang <91e0ff19c25a4c90f9bdc24b1ac8e48e9177c077@gmail.com>
Acked-by: Steven Whitehouse <9801c4ef11586b619a1c43ac9377eea2aee672dd@redhat.com>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs