staging: ft1000: remove obsolete driver

Remove support for Qleadtek Flash-OFDM modems. Telecom carrier is
discontinuing service for the radio technology.
See http://www.gtigroup.org/news/ind/2015-08-18/6996.html

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Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>