aspeed_defconfig: Enable SHMEM and TMPFS

Without enabling these options we get strange behaviour under qemu,
where it appears uevents aren't generated to create device nodes for
ttyS{0,4,5}. As a consequence we don't receive a getty on the console.

Cédric narrowed down the list of options initially at [1],
and with a patch to the qemu timer model[2] we can retain the
CONFIG_NO_HZ_IDLE=y configuration.

[1] https://github.com/openbmc/qemu/issues/4
[2] https://lists.ozlabs.org/pipermail/openbmc/2016-May/003209.html

Cc: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>

arch/arm/configs/aspeed_defconfig

@@ -13,7 +13,7 @@ CONFIG_BLK_DEV_INITRD=y
 # CONFIG_RD_LZ4 is not set
 CONFIG_CC_OPTIMIZE_FOR_SIZE=y
 CONFIG_BPF_SYSCALL=y
-# CONFIG_SHMEM is not set
+CONFIG_SHMEM=y
 # CONFIG_AIO is not set
 CONFIG_EMBEDDED=y
 # CONFIG_COMPAT_BRK is not set
@@ -127,6 +127,9 @@ CONFIG_FIRMWARE_MEMMAP=y
 CONFIG_FANOTIFY=y
 CONFIG_OVERLAY_FS=y
 CONFIG_CONFIGFS_FS=y
+CONFIG_TMPFS=y
+CONFIG_TMPFS_POSIX_ACL=y
+CONFIG_TMPFS_XATTR=y
 CONFIG_JFFS2_FS=y
 CONFIG_JFFS2_SUMMARY=y
 CONFIG_NFS_FS=y