af_unix: Add a prompt to CONFIG_AF_UNIX_OOB

This makes it possible to disable the MSG_OOB support in .config.

Signed-off-by: Florent Revest <revest@chromium.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241218143334.1507465-1-revest@chromium.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/unix/Kconfig

@@ -17,9 +17,11 @@ config UNIX
 	  Say Y unless you know what you are doing.
 
 config	AF_UNIX_OOB
-	bool
+	bool "UNIX: out-of-bound messages"
 	depends on UNIX
 	default y
+	help
+	  Support for MSG_OOB in UNIX domain sockets. If unsure, say Y.
 
 config UNIX_DIAG
 	tristate "UNIX: socket monitoring interface"