kmemleak: Renice the scanning thread to +10

This is a long-running thread but not high-priority. So it makes sense
to renice it to +10.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index e766e1d..6006553 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1039,6 +1039,7 @@
 	static int first_run = 1;
 
 	pr_info("Automatic memory scanning thread started\n");
+	set_user_nice(current, 10);
 
 	/*
 	 * Wait before the first scan to allow the system to fully initialize.