[patch] big whitespace cleanup in sys/kern/*

Hi.

I looked into sys/kern/* files to fix a bunch of common w/s style issues (221):
- leading space before label;
- leading space(s) before <tab>;
- space(s) instead of <tab>(s);
- space(s) in blank like.

I tried to be conservative and didn't touch semi-contrib files and
those with its own style.
Here is a diff I'd like someone look into and check in if there will
no objections.

-- 
wbr,
pluknet