fs/ocfs2: use sleeping version of __find_get_block()

This is a path that allows for blocking as it does IO. Convert
to the new nonatomic flavor to benefit from potential performance
benefits and adapt in the future vs migration such that semantics
are kept.

Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Link: https://kdevops.org/ext4/v6.15-rc2.html # [0]
Link: https://lore.kernel.org/all/aAAEvcrmREWa1SKF@bombadil.infradead.org/ # [1]
Link: https://lore.kernel.org/20250418015921.132400-5-dave@stgolabs.net


Tested-by:  <kdevops@lists.linux.dev>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>