spi: sh-msiof: Kill sh_msiof_spi_bits and sh_msiof_spi_hz functions

In the implementation of __spi_validate(), spi core will set transfer
bits_per_word and max speed as spi device default if it is not set for
this transfer. So we can remove the same implementation in this driver.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@linaro.org>