net: make NET_(DEV|NS)_REFCNT_TRACKER depend on NET

It makes little sense to ask if networking namespace or net device refcount
tracking shall be enabled for debug kernel builds without network support.

This is similar to the commit eb0b39ef ("net: CONFIG_DEBUG_NET depends
on CONFIG_NET").
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20220915124256.32512-1-lukas.bulwahn@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/Kconfig.debug

@@ -2,7 +2,7 @@
 
 config NET_DEV_REFCNT_TRACKER
 	bool "Enable net device refcount tracking"
-	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
+	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT && NET
 	select REF_TRACKER
 	default n
 	help
@@ -11,7 +11,7 @@ config NET_DEV_REFCNT_TRACKER
 
 config NET_NS_REFCNT_TRACKER
 	bool "Enable networking namespace refcount tracking"
-	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
+	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT && NET
 	select REF_TRACKER
 	default n
 	help