staging: kpc2000: kpc_spi: remove unnecessary struct member pin_dir

The structure kpc_spi, defined in in the kpc2000_spi driver, contains
a member named pin_dir which is never used after initialization.
Therefore, it should be removed for simplicity's sake.

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