IB/mlx4: fix unitialised variable is_mcast
IB/mlx4: fix unitialised variable is_mcast

Commit 297e0dad7206 ("IB/mlx4: Handle Ethernet L2 parameters for IP
based GID addressing") introduced a bug where is_mcast is now no
longer initialized on the non-multicast condition and so it can be
any random value from the stack.  This issue was detected by cppcheck:

    [drivers/infiniband/hw/mlx4/ah.c:103]: (error) Uninitialized
      variable: is_mcast

Simple fix is to initialise is_mcast to zero.

Signed-off-by: Colin Ian King <d100aa70785e45ee8deab668147d941941915c21@canonical.com>
Signed-off-by: Roland Dreier <0d270388f2f92757a5de0f4bd891d3b392c44c4f@purestorage.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs