suppress warning: "quotatypes" defined but not used

Suppress compilation warning: "quotatypes" defined but not used.
quotatypes is used only when CONFIG_QUOTA_DEBUG or CONFIG_PRINT_QUOTA_WARNING
is/are defined.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>