drm_mm fixes, take 3, final?

[Chris Wilson]

With a lot of polish applied, Joonas has reviewed the series - all but
for [04/38] "lib: Add a simple prime number generator"
[lib/prime_numbers.c]. Anyone feel like poking around at a bit of number
theory?

Other than it would appear to be ready for Daniel to sort out the merge
between drm-misc/i915... Please do take a look and see if you can spot
anything else that needs fixing/improving.
-Chris