xfs: add FALLOC_FL_ALLOCATE_RANGE to supported flags mask

Add FALLOC_FL_ALLOCATE_RANGE to the set of supported fallocate flags in
XFS_FALLOC_FL_SUPPORTED. This change improves code clarity and maintains
by explicitly showing this flag in the supported flags mask.

Note that since FALLOC_FL_ALLOCATE_RANGE is defined as 0x00, this addition
has no functional modifications.

Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>