icecc-create-env: Reformat

The environment script used an annoying mix of tabs and spaces and no
mapping of tabs to spaces would produce pleasant indentation. Reformat
to eliminate tab characters and settle on 4 spaces for indentation
(which matches the upstream icecream script from which this is derived)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>