[ofa-general] IPOIB_FLAG_UMCAST bit default value

[Or Gerlitz]

Roland,

I was asked... to check with you what's your take on having the
IPOIB_FLAG_UMCAST bit set by default? with the reasoning being that if
there's no rdma-cm user space multicast activity on the node for ipoib
group, then it has no influence and if there is such, the behavior of the
driver with this being flag set is typically what the user want, and where
this is not the case, they turn it off through sysfs.

Or.