drm/radeon/r7xx: fix copy paste typo in golden register setup

commit 022374c02e357ac82e98dd2689fb2efe05723d69 upstream.

Uses the wrong array size for some asics which can lead
to garbage getting written to registers.

Fixes:
https://bugzilla.kernel.org/show_bug.cgi?id=60674



Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>