configs/linux: Add CONFIG_MTD and CONFIG_MTD_POWERNV_FLASH

Signed-off-by: Sam Mendoza-Jonas <sam@mendozajonas.com>
diff --git a/openpower/configs/linux/skiroot_defconfig b/openpower/configs/linux/skiroot_defconfig
index 56d80ed..4c8059f 100644
--- a/openpower/configs/linux/skiroot_defconfig
+++ b/openpower/configs/linux/skiroot_defconfig
@@ -210,3 +210,5 @@
 CONFIG_XMON_DEFAULT=y
 # CONFIG_CRYPTO_ECHAINIV is not set
 # CONFIG_CRYPTO_HW is not set
+CONFIG_MTD=y
+CONFIG_MTD_POWERNV_FLASH=y