nati_x86_64_defconfig: build squashfs & overlayfs into the kernel

Switch squashfs from a module to a built in component of the kernel.
Also add overlayfs support to the kernel.  The new file layout requires
squashfs and overlayfs so they should be built in.

Signed-off-by: Bill Pittman <bill.pittman@ni.com>
Acked-by: Gratian Crisan <gratian.crisan@ni.com>
Natinst-ReviewBoard-ID: 294993

arch/x86/configs/nati_x86_64_defconfig

@@ -466,6 +466,7 @@ CONFIG_EXT3_FS_POSIX_ACL=y
 CONFIG_EXT3_FS_SECURITY=y
 # CONFIG_DNOTIFY is not set
 CONFIG_FUSE_FS=m
+CONFIG_OVERLAY_FS=y
 CONFIG_ISO9660_FS=y
 CONFIG_MSDOS_FS=y
 CONFIG_VFAT_FS=y
@@ -474,7 +475,7 @@ CONFIG_PROC_KCORE=y
 CONFIG_TMPFS_POSIX_ACL=y
 CONFIG_CONFIGFS_FS=y
 CONFIG_EFIVAR_FS=y
-CONFIG_SQUASHFS=m
+CONFIG_SQUASHFS=y
 CONFIG_SQUASHFS_XATTR=y
 CONFIG_NFS_FS=m
 CONFIG_NFS_V4=m