net: kcov: don't select SKB_EXTENSIONS when there is no NET

stable inclusion
from stable-5.10.64
commit 7ff0b71b6826ab93313af2c2a3e00c9dd93fb1b6
bugzilla: 182256 https://gitee.com/openeuler/kernel/issues/I4EG0U

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7ff0b71b6826ab93313af2c2a3e00c9dd93fb1b6

--------------------------------

commit 85ce50d3 upstream.

Fix kconfig warning when CONFIG_NET is not set/enabled:

WARNING: unmet direct dependencies detected for SKB_EXTENSIONS
  Depends on [n]: NET [=n]
  Selected by [y]:
  - KCOV [=y] && ARCH_HAS_KCOV [=y] && (CC_HAS_SANCOV_TRACE_PC [=y] || GCC_PLUGINS [=n])

Fixes: 6370cc3b ("net: add kcov handle to skb extensions")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Aleksandr Nogikh <nogikh@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20201110175746.11437-1-rdunlap@infradead.orgSigned-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

lib/Kconfig.debug

@@ -1885,7 +1885,7 @@ config KCOV
 	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
 	select DEBUG_FS
 	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
-	select SKB_EXTENSIONS
+	select SKB_EXTENSIONS if NET
 	help
 	  KCOV exposes kernel code coverage information in a form suitable
 	  for coverage-guided fuzzing (randomized testing).