xprtrdma: Remove include for linux/prefetch.h

Clean up. This include should have been removed by
commit 23826c7aeac7 ("xprtrdma: Serialize credit accounting again").

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
1 file changed