staging: kpc2000: remove unnecessary debug prints in kpc_dma_driver.c

Debug prints that are used only to inform about function entry or exit
can be removed as ftrace can be used to get this information.

Signed-off-by: Simon Sandström <simon@nikanor.nu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>