enic: fix return values in enic_set_coalesce

enic_set_coalesce() has two problems.

* It should return -EINVAL and not -EOPNOTSUPP for invalid coalesce values.

* In case of MSIX, enic_set_coalesce return error after applying requested
  coalescing setting partially. We should either apply all the setting requeste
  and return success or apply non and return error.

* This patch also simplifies the algo.

This was introduced by
'7c2ce6e6 enic: Add support for adaptive interrupt coalescing'

These changes were suggested by Ben Hutchings here
http://www.spinics.net/lists/netdev/msg283972.html



Also change enic driver version.

Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>