media: amphion: Fix firmware path to match linux-firmware

The path did not match the one it was submitted into linux-firmware
which prevented generic distribution from having working CODEC.

Fixes: 9f599f35 ("media: amphion: add vpu core driver")
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>