Use NTR rather than NTR as prefix for Netronome vendor id

Use NTR rather than NTR as prefix for Netronome vendor id

As pointed out by Ben Pfaff NTR (NetronoMe eXtension) is confusingly
similar to NXM (Nicira eXtended Match?) which is already used widely
in the Open vSwitch tree.

To get ease future eye strain use NTR (NeTRonome) instead of NTR,
starting with the only instance currently present in the tree,
the Netronome vendor id.

This is in preparation for actually using the Netronome vendor id.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>