package/kodi: bump version to 15.0 Isengard

package/kodi: bump version to 15.0 Isengard

- added libsquish as new dependency
  https://github.com/xbmc/xbmc/commit/f73653d62b09db8cab7662ae7c4b2dab596b4ab0#diff-3b3a6ec97232deb43dc14319a73872c1R2207

- updated build procedure for host version of texturepacker

- removed SDL dependencies
  http://kodi.wiki/view/Kodi_v15_%28Isengard%29_changelog#Linux_Specific
  "Removed dependencies of SDL (Simple DirectMedia Layer) for everything
   but hardware abstraction for input devices"

- added mips support:
  https://github.com/xbmc/xbmc/commit/5d1746ad5b2272ba5f906ad9a49a87b650bda14a

[Thomas:
 - don't do a manual fixup of kodi-config.cmake, and instead patch it
   to use CMAKE_FIND_ROOT_PATH. This will also avoid having to pass
   -DCMAKE_MODULE_PATH to all Kodi add-ons .mk files.]

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>