IB/core: avoid 32-bit warning

The INIT_UDATA() macro requires a pointer or unsigned long argument for
both input and output buffer, and all callers had a cast from when
the code was merged until a recent restructuring, so now we get

core/uverbs_cmd.c: In function 'ib_uverbs_create_cq':
core/uverbs_cmd.c:1481:66: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]

This makes the code behave as before by adding back the cast to
unsigned long.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 565197dd ("IB/core: Extend ib_uverbs_create_cq")
Reviewed-by: Yann Droneaud <ydroneaud@opteya.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/uverbs_cmd.c

@@ -1478,7 +1478,7 @@ ssize_t ib_uverbs_create_cq(struct ib_uverbs_file *file,
 	if (copy_from_user(&cmd, buf, sizeof(cmd)))
 		return -EFAULT;
 
-	INIT_UDATA(&ucore, buf, cmd.response, sizeof(cmd), sizeof(resp));
+	INIT_UDATA(&ucore, buf, (unsigned long)cmd.response, sizeof(cmd), sizeof(resp));
 
 	INIT_UDATA(&uhw, buf + sizeof(cmd),
 		   (unsigned long)cmd.response + sizeof(resp),