staging: kpc2000: kpc_spi: remove function kp_spi_bytes_per_word()

The static function kp_spi_bytes_per_word() is defined in kpc2000_spi.c,
but it is completely unused. As this function is unused, it can and
should be removed.

Signed-off-by: Geordan Neukum <gneukum1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>