sluinit: Clean up comments
sluinit: Clean up comments

Convert

/*
 * ...
 * ...
 */

style comments to

// ...
// ...

Also, clean up the comment text in general and try to make it more
consistent.

Signed-off-by: Patrick Colp <28b178ad2ea524258cc96f810e0c5ccaaabfaf13@oracle.com>

u-root/u-root,u-root/u-root,u-root/u-root