ALSA: aoa: Remove redundant size arguments from strscpy()

The size parameter of strscpy() is optional if the destination buffer
has a fixed length and strscpy() can automatically determine its size
using sizeof(). This makes many explicit size arguments redundant.

Remove them to shorten and simplify the code.

No functional changes intended.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Takashi Iwai <tiwai@suse.de>