This commit is required to uplift a wr-switch kernel version

Since the kernel commit
850a545bd net: validate HWTSTAMP ioctl parameters
Follows: v3.1-rc9
Precedes: v3.2-rc1
SIOCSHWTSTAMP ioctl check whether field "flags" of struct hwtstamp_config
is empty, otherwise ioctl returns -EINVAL
Signed-off-by: Adam Wujek <adam.wujek@cern.ch>