spi: sh-msiof: Restrict bits per word to 8/16/24/32 on R-Car Gen2/3

While the MSIOF variants in older SuperH and SH/R-Mobile SoCs support
bits-per-word values in the full range 8..32, the variants present in
R-Car Gen2 and Gen3 SoCs are restricted to 8, 16, 24, or 32.

Obtain the value from family-specific sh_msiof_chipdata to fix this.

Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Mark Brown <broonie@kernel.org>