meta-google: busybox: enable cpio output

Kdump preprocessing needs to read, modify, and repack a initfs, this is to enable cpio
-O option.

Change-Id: I3f59da1ad0094bbf4a0ef58094a26dfac3423f1d
Signed-off-by: Yuxiao Zhang <yuxiaozhang@google.com>
diff --git a/meta-google/recipes-core/busybox/files/gbmc.cfg b/meta-google/recipes-core/busybox/files/gbmc.cfg
index 9b053c7..bb74f6a 100644
--- a/meta-google/recipes-core/busybox/files/gbmc.cfg
+++ b/meta-google/recipes-core/busybox/files/gbmc.cfg
@@ -25,6 +25,7 @@
 CONFIG_FEATURE_TOP_SMP_CPU=y
 CONFIG_FEATURE_TOP_SMP_PROCESS=y
 CONFIG_FEATURE_TOPMEM=y
+CONFIG_FEATURE_CPIO_O=y
 
 # Remove unused things
 CONFIG_BUNZIP2=n