NFSD: Fix inconsistent indenting

Eliminate the follow smatch warning:

fs/nfsd/nfs4xdr.c:4766 nfsd4_encode_read_plus_hole() warn: inconsistent
indenting.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>