kbuild: Call gzip with -n

The timestamps recorded in the .gz files add no value.

Signed-off-by: Michal Marek <mmarek@suse.cz>
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 1c702ca..93b2b59 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -197,7 +197,7 @@
 # ---------------------------------------------------------------------------
 
 quiet_cmd_gzip = GZIP    $@
-cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -f -9 > $@) || \
+cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -n -f -9 > $@) || \
 	(rm -f $@ ; false)
 
 # DTC