fix brace mismatch in winami.c

fix brace mismatch in winami.c

Reported directly to devteam, so no #H number.  Conditional code in
amii_get_ext_cmd() included an unmatched '{', which would break
compilation (at least if EXTMENU was enabled) and also resulted in
the remainder of winami.c being mis-formatted (the functions there
were treated as being inside a block rather than at file level).

This is completely untested.

There's some code suppressed via '#if 0' with a comment "fix for PL2".
We haven't used the patch-level nomenclature since version 3.0!