[PATCH net] ipmr: fix build with clang and DEBUG_NET disabled.

[Paolo Abeni <pabeni@redhat.com>]

Sasha reported a build issue in ipmr::

net/ipv4/ipmr.c:320:13: error: function 'ipmr_can_free_table' is not \
	needed and will not be emitted \
	[-Werror,-Wunneeded-internal-declaration]
   320 | static bool ipmr_can_free_table(struct net *net)

Apparently clang is too smart with BUILD_BUG_ON_INVALID(), let's
fallback to a plain WARN_ON_ONCE().

Reported-by: Sasha Levin <sashal@kernel.org>
Closes: https://qa-reports.linaro.org/lkft/sashal-linus-next/build/v6.11-25635-g6813e2326f1e/testrun/26111580/suite/build/test/clang-nightly-lkftconfig/details/
Fixes: 11b6e701bce9 ("ipmr: add debug check for mr table cleanup")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/ipv4/ipmr.c  | 2 +-
 net/ipv6/ip6mr.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 383ea8b91cc7..c5b8ec5c0a8c 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -437,7 +437,7 @@ static void ipmr_free_table(struct mr_table *mrt)
 {
 	struct net *net = read_pnet(&mrt->net);
 
-	DEBUG_NET_WARN_ON_ONCE(!ipmr_can_free_table(net));
+	WARN_ON_ONCE(!ipmr_can_free_table(net));
 
 	timer_shutdown_sync(&mrt->ipmr_expire_timer);
 	mroute_clean_tables(mrt, MRT_FLUSH_VIFS | MRT_FLUSH_VIFS_STATIC |
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 4147890fe98f..7f1902ac3586 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -416,7 +416,7 @@ static void ip6mr_free_table(struct mr_table *mrt)
 {
 	struct net *net = read_pnet(&mrt->net);
 
-	DEBUG_NET_WARN_ON_ONCE(!ip6mr_can_free_table(net));
+	WARN_ON_ONCE(!ip6mr_can_free_table(net));
 
 	timer_shutdown_sync(&mrt->ipmr_expire_timer);
 	mroute_clean_tables(mrt, MRT6_FLUSH_MIFS | MRT6_FLUSH_MIFS_STATIC |
-- 
2.45.2