uboot-imx

fs/fat: Clean up open-coded sector <-> cluster conversions

Use the clust_to_sect() helper that was introduced earlier, and add an
inverse sect_to_clust(), plus update the various spots that open-coded
this conversion previously.

Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>