aec62xx: kill speedproc() method wrapper (take 2)

There's no reason to have the speedproc() method wrapper for the two quite
different chip families, so just get rid of it.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>