ALSA: echoaudio: Avoid non-standard macro usage

Pass the device pointer from the PCI pointer directly, instead of a
non-standard macro.  The macro didn't give any better readability.

Also slightly refactor the code (drop the return value check from the
preallocation) as it never returns an error.

Link: https://lore.kernel.org/r/20191105151856.10785-21-tiwai@suse.de


Signed-off-by: Takashi Iwai <tiwai@suse.de>