TIOCSTI: Document CAP_SYS_ADMIN behaviour in Kconfig

Clarifies that the LEGACY_TIOCSTI setting is safe to turn off even
when running BRLTTY, as it was introduced in commit 690c8b8
("TIOCSTI: always enable for CAP_SYS_ADMIN").

Signed-off-by: Günther Noack <[email protected]>
Reviewed-by: Samuel Thibault <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: gnoack

drivers/tty/Kconfig

@@ -164,6 +164,9 @@ config LEGACY_TIOCSTI
 	  userspace depends on this functionality to continue operating
 	  normally.
 
+	  Processes which run with CAP_SYS_ADMIN, such as BRLTTY, can
+	  use TIOCSTI even when this is set to N.
+
 	  This functionality can be changed at runtime with the
 	  dev.tty.legacy_tiocsti sysctl. This configuration option sets
 	  the default value of the sysctl.