configs/qemu: enable tmpfs for or1k

This is used by buildroot default initscripts and results in some ugly
errors on startup otherwise.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

board/qemu/or1k/linux-4.9.config

@@ -14,6 +14,7 @@ CONFIG_IP_MULTICAST=y
 # CONFIG_WIRELESS is not set
 CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
+CONFIG_TMPFS=y
 CONFIG_NETDEVICES=y
 CONFIG_ETHOC=y
 # CONFIG_WLAN is not set