ANDROID: netfilter: xt_qtaguid: don't check if embedded arrays are NULL

clang warns about four NULL pointer checks:

net/netfilter/xt_qtaguid.c:973:11: warning: address of array 'ifa->ifa_label' will always evaluate to 'true' [-Wpointer-bool-conversion]
net/netfilter/xt_qtaguid.c:974:13: warning: address of array 'ifa->ifa_label' will always evaluate to 'true' [-Wpointer-bool-conversion]
net/netfilter/xt_qtaguid.c:1212:31: warning: address of array 'el_dev->name' will always evaluate to 'true' [-Wpointer-bool-conversion]
net/netfilter/xt_qtaguid.c:1640:31: warning: address of array 'el_dev->name' will always evaluate to 'true' [-Wpointer-bool-conversion]

Both of these fields are embedded char[16] arrays rather than pointers,
so they can never be NULL.

Change-Id: I748ff6dd11569e5596a9d5cecdf9c334847e7307
Signed-off-by: Greg Hackmann <ghackmann@google.com>