erofs: Revert "erofs: fix kvcalloc() misuse with __GFP_NOFAIL"

Let's revert commit 12724ba3 ("erofs: fix kvcalloc() misuse with
__GFP_NOFAIL") since kvmalloc() already supports __GFP_NOFAIL in commit
a421ef30 ("mm: allow !GFP_KERNEL allocations for kvmalloc").  So
the original fix was wrong.

Actually there was some issue as [1] discussed, so before that mm fix
is landed, the warn could still happen but applying this commit first
will cause less.

[1] https://lore.kernel.org/r/20230305053035.1911-1-hsiangkao@linux.alibaba.com

Fixes: 12724ba3

 ("erofs: fix kvcalloc() misuse with __GFP_NOFAIL")
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20230309053148.9223-1-hsiangkao@linux.alibaba.com


Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>