kmsxx: new package

kmsxx: new package

KMS++ is a suite of library and test tools to interact with KMS drivers in
the linux kernel.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
[Thomas:
 - rename prompt to kms++, suggested by Yann E. Morin
 - fixup the thread dependency comment
 - remove the mention of the python wrapper in the Config.in help
   text, since they are not installed
 - fix the Config.in comment to mention the C++ and gcc >= 4.8
   dependencies
 - use = instead of += when appropriate
 - use a loop to install the test programs
 - use a loop to install the libraries
 - add installation to staging as well, both the libraries and header
   files
 - add missing dependency on host-pkgconf
 - add hash file.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>