btrfs: unify extent_page_data type passed as void

Functions called from extent_write_cache_pages used void* as generic
callback data, but all of them convert it to extent_page_data, or use it
directly.

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2017-11-30 18:00:02 +01:00
commit aab6e9edf0