ALSA: echoaudio: purge contradictions between dimension matrix members and total number of members

Currently, sound device drivers for PCI cards produced by Echo Audio
support dimension parameter of element information. But the information
has contradictions to the number of members of each element. I guess that
this comes from the assumption that these sound cards are used only by
'echomixer' in userspace. But ideally, they should be used with usual ALSA
control applications.

This commit removes the contradiction. As a result, 'Monitor Mixer Volume'
and 'VMixer Volume' elements are shown in usual ALSA control applications
such as 'amixer' and 'alsamixer' in series.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>