ALSA: au88x0: Remove unneeded variable: "changed"

Fix below issues reported by coccicheck

sound/pci/au88x0/au88x0_a3d.c:821:8-15: Unneeded variable: "changed".
Return "1" on line 834
sound/pci/au88x0/au88x0_a3d.c:768:5-12: Unneeded variable: "changed".
Return "1" on line 777
sound/pci/au88x0/au88x0_a3d.c:804:5-12: Unneeded variable: "changed".
Return "1" on line 813
sound/pci/au88x0/au88x0_a3d.c:786:8-15: Unneeded variable: "changed".
Return "1" on line 796

Signed-off-by: Hariprasad Kelam <hariprasad.kelam@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>