netifd: rename 20-smp-tune to 20-smp-packet-steering

Rename the script to be more obvious that this is for
packet steering only.

Signed-off-by: Alan Swanson <reiver@improbability.net>

diff --git a/package/network/config/netifd/files/etc/hotplug.d/net/20-smp-tune b/package/network/config/netifd/files/etc/hotplug.d/net/20-smp-packet-steering
similarity index 100%
rename from package/network/config/netifd/files/etc/hotplug.d/net/20-smp-tune
rename to package/network/config/netifd/files/etc/hotplug.d/net/20-smp-packet-steering