ctl: fix a test for user-defined element set in a point of dimension

ctl: fix a test for user-defined element set in a point of dimension

Currently, this test program has a bug related to dimension information.
When testing an element set with byte type, the program adds 512 members
to an element. This is a maximum number permitted for this type.

On the other hand, dimension information of the elements consists of
[8, 4, 8, 4]. Calculated members in the multi-dimensional matrix is 1024.
This should be less than 512.

This commit fixes the bug.

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