Bump version to v1.7.0

It's been rather too long since the last release, and quite a lot of
changes have accumulated.  Finally get around to rolling a release.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

Makefile

@@ -10,8 +10,8 @@
 # CONFIG_LOCALVERSION from some future config system.
 #
 VERSION = 1
-PATCHLEVEL = 6
+PATCHLEVEL = 7
-SUBLEVEL = 1
+SUBLEVEL = 0
 EXTRAVERSION =
 LOCAL_VERSION =
 CONFIG_LOCALVERSION =