hugetlb: remove unnecessary nid initialization

nid is initialized to numa_node_id() but will either be overwritten in
the loop or not used in the conditional. So remove the initialization.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>