net/handshake: Squelch allocation warning during Kunit test

The "handshake_req_alloc excessive privsize" kunit test is intended
to check what happens when the maximum privsize is exceeded. The
WARN_ON_ONCE_GFP at mm/page_alloc.c:4744 can be disabled safely for
this test.
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Fixes: 88232ec1 ("net/handshake: Add Kunit tests for the handshake consumer API")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/168451636052.47152.9600443326570457947.stgit@oracle-102.nfsv4bat.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/handshake/handshake-test.c

@@ -102,7 +102,7 @@ struct handshake_req_alloc_test_param handshake_req_alloc_params[] = {
 	{
 		.desc			= "handshake_req_alloc excessive privsize",
 		.proto			= &handshake_req_alloc_proto_6,
-		.gfp			= GFP_KERNEL,
+		.gfp			= GFP_KERNEL | __GFP_NOWARN,
 		.expect_success		= false,
 	},
 	{