Fix grabbing lock from atomic context in i2c driver

[jeanlemotan]

2 main changes:

• check for timeouts in the bcm2708_bsc_setup function as indicated by this comment:
  /* poll for transfer start bit (should only take 1-20 polls) */
  This implies that the setup function can now fail so account for this everywhere it's called
• Removed the clk_get_rate call from inside the setup function as it locks a mutex and that's not ok since we call it from under a spin lock.

[popcornmix]

Would be nice if first line of commit message was more descriptive.
Update i2c-bcm2708.c doesn't really describe the commit.
"Fix grabbing lock from atomic context in i2c driver" would be clearer.

[jeanlemotan]

Apologies for the commit message. I was so focused not to mess up the commit that the message slipped.

Anyway, you are right about the whitespace changes. I will separate the commit in 3 parts - one for cosmetics and 2 for each of the issues (timeouts and clk_get_rate).

Now the main problem is that I'm a complete rookie when it comes to git (I usually download the zip from github) so squashing the commits will keep me busy for a few evenings. I guess it's time I figure git out.

[popcornmix]

Basically just concentrate on making your local patch-2 branch look correct.
Use:
git rebase -i HEAD~2
and follow the suggestions. Once done:
git push -f
will update this PR.

[jeanlemotan]

Done. Updated the comment, removed commented code, fixed a typo and squashed the commits.