IB/core: Fix build failure without hugepages

HPAGE_SHIFT is only defined on architectures that support hugepages:

drivers/infiniband/core/umem_odp.c: In function 'ib_umem_odp_get':
drivers/infiniband/core/umem_odp.c:245:26: error: 'HPAGE_SHIFT' undeclared (first use in this function); did you mean 'PAGE_SHIFT'?

Enclose this in an #ifdef.

Fixes: 9ff1b6466a ("IB/core: Fix ODP with IB_ACCESS_HUGETLB handling")
Link: https://lore.kernel.org/r/20200109084740.2872079-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/umem_odp.c

@@ -241,10 +241,11 @@ struct ib_umem_odp *ib_umem_odp_get(struct ib_udata *udata, unsigned long addr,
 	umem_odp->umem.owning_mm = mm = current->mm;
 	umem_odp->notifier.ops = ops;
 
+	umem_odp->page_shift = PAGE_SHIFT;
+#ifdef CONFIG_HUGETLB_PAGE
 	if (access & IB_ACCESS_HUGETLB)
 		umem_odp->page_shift = HPAGE_SHIFT;
-	else
-		umem_odp->page_shift = PAGE_SHIFT;
+#endif
 
 	umem_odp->tgid = get_task_pid(current->group_leader, PIDTYPE_PID);
 	ret = ib_init_umem_odp(umem_odp, ops);