coverity: ifr_name buffer not NULL terminated

The kernel (net/core/dev_ioctl.c:dev_ioctl()) is going to NULL terminate
this name after the copy-in of the ifr, so even though this is a fixed
sized array the last byte isn't usable as part of the name. All the ioctls
we're using go through this code path.

Use the ifr name in the DEBUG message in case it was possibly truncated.

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>