open-plc-utils: new package

[Thomas:
  - rename to open-plc-utils to match upstream name.
  - fix Config.in to use tabs instead of spaces
  - remove 'default n' line
  - add dependency on BR2_USE_MMU
  - bump to a more recent upstream commit
  - remove no longer needed openplc-0002-Remove-vfprintf-call.patch
  - rename patch to the proper naming convention
  - specify <pkg>_LICENSE_FILES
  - pass CROSS= instead of CC=
  - do not pass CC= at install time.]

Signed-off-by: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>