dax,ext2: replace xip_truncate_page with dax_truncate_page

dax,ext2: replace xip_truncate_page with dax_truncate_page

It takes a get_block parameter just like nobh_truncate_page() and
block_truncate_page()

Signed-off-by: Matthew Wilcox <[email protected]>
Reviewed-by: Mathieu Desnoyers <[email protected]>
Cc: Andreas Dilger <[email protected]>
Cc: Boaz Harrosh <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Ross Zwisler <[email protected]>
Cc: Theodore Ts'o <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>