NFSD: Check layout type when returning client layouts

According to RFC5661:
" When lr_returntype is LAYOUTRETURN4_FSID, the current filehandle is used
   to identify the file system and all layouts matching the client ID,
   the fsid of the file system, lora_layout_type, and lora_iomode are
   returned.  When lr_returntype is LAYOUTRETURN4_ALL, all layouts
   matching the client ID, lora_layout_type, and lora_iomode are
   returned and the current filehandle is not used. "

When returning client layouts, always check layout type.

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>