[PATCH] samples/watch_test - fix build error

[Valdis KlÄtnieks]

We're missing a depends in the Kconfig, which can lead to trying to
build without the required headers being present..

  HOSTCC  samples/watch_queue/watch_test
samples/watch_queue/watch_test.c:23:10: fatal error: linux/watch_queue.h: No such file or directory
   23 | #include <linux/watch_queue.h>
      |          ^~~~~~~~~~~~~~~~~~~~~
compilation terminated.
make[2]: *** [scripts/Makefile.host:107: samples/watch_queue/watch_test] Error 1

Signed-off-by: Valdis Kletnieks <valdis.kletnieks@xxxxxx>

---
diff --git a/samples/Kconfig b/samples/Kconfig
index 2c3e07addd38..d0761f29ccb0 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -171,6 +171,7 @@ config SAMPLE_VFS
 
 config SAMPLE_WATCH_QUEUE
 	bool "Build example /dev/watch_queue notification consumer"
+	depends on HEADERS_INSTALL
 	help
 	  Build example userspace program to use the new mount_notify(),
 	  sb_notify() syscalls and the KEYCTL_WATCH_KEY keyctl() function.