RDMA/uverbs: Convert to use ERR_CAST()

JIRA: https://issues.redhat.com/browse/RHEL-110100

commit 7bc871a
Author: Li Haoran <li.haoran7@zte.com.cn>
Date:   Tue Apr 1 21:09:23 2025 +0800

    RDMA/uverbs: Convert to use ERR_CAST()

    As opposed to open-code, using the ERR_CAST macro clearly indicates that
    this is a pointer to an error value and a type conversion was performed.

    Link: https://patch.msgid.link/r/202504012109233981_YPVbd4wQzmAzP3tA5IG@zte.com.cn
    Signed-off-by: Li Haoran <li.haoran7@zte.com.cn>
    Signed-off-by: Shao Mingyin <shao.mingyin@zte.com.cn>
    Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Signed-off-by: Kamal Heib <kheib@redhat.com>

Author: Kamalheib

drivers/infiniband/core/uverbs_cmd.c

@@ -193,7 +193,7 @@ _ib_uverbs_lookup_comp_file(s32 fd, struct uverbs_attr_bundle *attrs)
 					       fd, attrs);
 
 	if (IS_ERR(uobj))
-		return (void *)uobj;
+		return ERR_CAST(uobj);
 
 	uverbs_uobject_get(uobj);
 	uobj_put_read(uobj);