AM30: patch for thinko in my previous patch

[Philip Blundell]

>It turned out that the insns marked as AM30 are *not* supposed to be
>available on AM33, so the patch was wrong.  Nevertheless, there's
>still a severe bug on current CVS (release branch included), that
>causes it to reject any AM30-specific instructions.  Here's a patch.
>Ok to install?

I see this was approved for the trunk; it is OK for the release branch also.

p.