staging: kpc2000: dma_common_defs.h: remove unused inline functions

The functions GetBackEndStatus() and BackEndControlSetClear() are never
used by any code, so just remove them.

Cc: Matt Sickler <Matt.Sickler@daktronics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>