RDMA/vmw_pvrdma: Add shared receive queue support

Add the required functions needed to support SRQs. Currently, kernel
clients are not supported. SRQs will only be available in userspace.

Reviewed-by: Adit Ranadive <aditr@vmware.com>
Reviewed-by: Aditya Sarwade <asarwade@vmware.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Reviewed-by: Nitish Bhat <bnitish@vmware.com>
Signed-off-by: Bryan Tan <bryantan@vmware.com>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>