When refining mask/interval parameters, helper functions can return error
code. This error is not handled immediately. This seems to return
parameters to userspace applications in its meddle of processing.

However, in general, when receiving error from system calls, the
application might not handle argument buffer. It's reasonable to
judge the above design as superfluity.

This commit handles the error immediately.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>