fs: remove unnecessary new/huge_valid_dev check

Hi Andrew,

Could you please consider take patchset to mm-tree:

http://marc.info/?l=linux-kernel&m=144344695929685&w=2

This patchset removes unnessary new_valid_dev() check in several filesystems because this function always return true.

This patchset also removes huge_valid_dev() function because there's no user of this function at all.

Once you take this patchset i'll send another patch to remove new_valid_dev() with its last user at all.

This patchset received several Acked-by and Reviewed-by from each fs maintainers. Please see the thread.

Thanks
Bai