Merge branch 'tipc-Confgiuration-of-MTU-for-media-UDP'

GhantaKrishnamurthy MohanKrishna says:

====================
tipc: Confgiuration of MTU for media UDP

Systematic measurements have shown that an emulated MTU of 14k for
UDP bearers is the optimal value for maximal throughput. Accordingly,
the default MTU of UDP bearers is changed to 14k.

We also provide users with a fallback option from this value,
by providing support to configure MTU for UDP bearers. The following
options are introduced which are symmetrical to the design of
confguring link tolerance.

- Configure media with new MTU value, which will take effect on
links going up after the moment it was configured. Alternatively,
the bearer has to be disabled and re-enabled, for existing links to
reflect the configured value.

- Configure bearer with new MTU value, which take effect on
running links dynamically.

Please note:
- User has to change MTU at both endpoints, otherwise the link
will fall back to smallest MTU after a reset.
- Failover from a link with higher MTU to a link with lower MTU
====================

Signed-off-by: David S. Miller <davem@davemloft.net>