Revert "IPoIB: No longer use flush as a parameter"

This reverts commit ce347ab90eaabc69a6146d41943981d51e7a9b82.

The series of IPoIB bug fixes that went into 3.19-rc1 introduce
regressions, and after trying to sort things out, we decided to revert
to 3.18's IPoIB driver and get things right for 3.20.

Signed-off-by: Roland Dreier <roland@purestorage.com>

diff --cc drivers/infiniband/ulp/ipoib/ipoib.h
Simple merge

diff --cc drivers/infiniband/ulp/ipoib/ipoib_ib.c
Simple merge

diff --cc drivers/infiniband/ulp/ipoib/ipoib_main.c
Simple merge