doc/vm: fix typo in the hugetlb admin documentation

Change 'pecify' to 'Specify'.

Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lkml.kernel.org/r/20200723032248.24772-4-bhe@redhat.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>