sif: Lift sif_verbs up to be independent of sif internal headers

sif: Lift sif_verbs up to be independent of sif internal headers

The sif_verbs.h file needs to be independent of
other header files to be includable from other kernel.
This is necessary to avoid duplicate definition of
the API elements. For Oracle Linux this file now moves from
drivers/infiniband/hw/sif/ to include/rdma/ to make it
available for the RDS and uvNIC drivers.

This is a temporary but necessary measure while we wait
for proper generic interfaces to be defined at the common
verbs layer.

Orabug: 24524698

Signed-off-by: Knut Omang <knut.omang@oracle.com>