spi: tegra: Use DIV_ROUND_UP instead of open coded

This also makes the intention more clear.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

diff --cc drivers/spi/spi-tegra114.c
Simple merge

diff --cc drivers/spi/spi-tegra20-sflash.c
Simple merge

diff --cc drivers/spi/spi-tegra20-slink.c
Simple merge