cpu/apic: multiple trivial cleanups

[00xc]

• Add documentation for several functions.
• Remove the pub qualifier from functions that are not used outside the APIC module.
• Clean up formatting in some comments
• Make a few variables immutable.

[msft-jlange]

I'm not sure we want to spend much effort converting the number of spaces after periods in comments. The VIM editor, for example (which I use) defaults to two spaces after a period when joining two comment lines together. I don't object to changes to these comments but we could easily wind up wasting a lot of time with comment editing if we try to get strict about requiring specific rules.

[00xc]

I'm not sure we want to spend much effort converting the number of spaces after periods in comments. The VIM editor, for example (which I use) defaults to two spaces after a period when joining two comment lines together. I don't object to changes to these comments but we could easily wind up wasting a lot of time with comment editing if we try to get strict about requiring specific rules.

I just did a quick search & replace, I don't think we should enforce it as a rule.

[msft-jlange]

@00xc, this has been pending update for a while. Would you like me to take over the PR and complete it, or did you want to continue to update it yourself?

[00xc]

@00xc, this has been pending update for a while. Would you like me to take over the PR and complete it, or did you want to continue to update it yourself?

Should be good to go now

[msft-jlange]

I still don't like all of the double- to single-space changes because it introduces a lot of noise into the diff (it makes it harder to see the substantive changes because they're mixed in with a lot of whitespace changes) but the rest of the change looks good.