spi/xilinx: Convert bits_per_word in bytes_per_word
spi/xilinx: Convert bits_per_word in bytes_per_word

Simplify the code by using the unit used on most of the code logic.

Signed-off-by: Ricardo Ribalda Delgado <39bb74b16720293e1449e36465485b27216fbd6d@gmail.com>
Signed-off-by: Mark Brown <b51b9a92386687a9ac927cebfa0f978adeb8cea5@kernel.org>

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