spi: sh-msiof: Remove sh_msiof_spi_priv.chipdata

After probe time, the pointer to the sh_msiof_chipdata structure in the
sh_msiof_spi_priv structure is used only for checking the SPI master flags.
As these are also available in the spi_master structure, convert the
users to access those, and remove the pointer.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>