openpower/configs: Enable PETITBOOT_MTD by default

Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
diff --git a/openpower/configs/garrison_defconfig b/openpower/configs/garrison_defconfig
index eafb6d5..9cb67f8 100644
--- a/openpower/configs/garrison_defconfig
+++ b/openpower/configs/garrison_defconfig
@@ -63,6 +63,7 @@
 BR2_PACKAGE_NETCAT=y
 BR2_PACKAGE_RSYNC=y
 BR2_PACKAGE_PETITBOOT=y
+BR2_PACKAGE_PETITBOOT_MTD=y
 BR2_PACKAGE_IPMITOOL=y
 BR2_PACKAGE_POWERPC_UTILS=y
 BR2_PACKAGE_MDADM=y