spi: sun4i: Set bits_per_word_mask to only support 8 bits word length
spi: sun4i: Set bits_per_word_mask to only support 8 bits word length

This controller only supports 8 bits word length.
Set bits_per_word_mask so spi core will reject transfers that attempt to use
an unsupported bits_per_word value.

Signed-off-by: Axel Lin <b6ffd6973e972cb999e8e535ab74da7fee0c035f@ingics.com>
Acked-by: Maxime Ripard <2d324f4ca95610bde432fa2af2f28cd21110687d@free-electrons.com>
Signed-off-by: Mark Brown <b51b9a92386687a9ac927cebfa0f978adeb8cea5@linaro.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs