[ALSA] Remove indirect control access

This patch removes the indirect control access to the control elements.
The indirect access has never been used and is even broken on 32bit
ioctl wrapper.  Let's clean it up.
The pointers still remain in snd_ctl_elem_* structs just to make sure
that the struct size won't change.  Once after checking the size
consistency, we can get rid of them, too.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>