Remove the knlinfo and mkknlimg tools

The canonical home of the mkknlimg and knlinfo tools is now the Linux
tree in the scripts directory. Different branches may contain different
versions making external copies such as these likely to be inconsistent
with at least one of them, so delete the the copies.

See: #58

Author: Phil Elwell

mkimage/README

@@ -0,0 +1,6 @@
+The mkknlimg and knlinfo utilities are now found in the scripts directory
+of the Linux tree, where they are covered by the kernel licence.
+
+Note also that the firmware shipped with 4.4 kernels now assumes the kernel
+is Device Tree-capable unless there is a trailer to say otherwise, meaning
+that these tools aren't needed for most situations.