drm/nouveau/disp/gt215: Fix HDA ELD handling (thus, HDMI audio) on gt215

commit d347583a upstream.

Store the ELD correctly, not just enough copies of the first byte
to pad out the given ELD size.

Signed-off-by: Alastair Bridgewater <alastair.bridgewater@gmail.com>
Fixes: 120b0c39 ("drm/nv50-/disp: audit and version SOR_HDA_ELD method")
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>