The available platforms in the ndk might not be the same as in the sdk.
This patch is renames everything using the ndk platform list to
ndkPlatforms, except the highestAvailablePlatform which wrongly uses
the ndk platform list.

Change-Id: I02d9b68bbc27b0c748281678fe654d5f4244578d
Reviewed-by: BogDan Vatra <bogdan@kde.org>