device_pager: user iterators to free device pages

[dougm]

Summary

Change cdev_mgtdev_page_free_page to take an iterator, rather than an object and page, so that removing the page from the object radix tree can take advantage of locality with iterators. Define a general-purpose function to free multiple pages, which can be used in several places.

[dougm]

Fix typo in tegra_bo.c.

[markj]

sys/vm/device_pager.c

267

291

Looking at the callers of cdev_mgtdev_pager_free_pages(), I believe that in all cases the page count is simply the number of resident pages in the object. In that case, I would suggest simply iterating over all pages in the object and freeing them, rather than passing this count.

[dougm]

Drop length argument to cdev_mgtdev_pager_free_pages().