add_control_with_pfx() in hda_generic.c assumes a shorter name string
for the control element, and this resulted in the truncation of the
long but valid string like "Headphone Surround Switch" in the middle.

This patch aligns the max size to the actual limit of snd_ctl_elem_id,
44.

Cc: <stable@vger.kernel.org> [v3.9+]
Signed-off-by: Takashi Iwai <tiwai@suse.de>