Amiga: more review fixes

- NHW_BASE / NHW_OVER collided with NHW_PERMINVENT=6; renumber off NHW_LAST_TYPE.
- GlyphToIcon used > 10000 instead of >=.
- make_menu_items sized array by sizeof(amii_menu_item) instead of menu_item.
- DoMenuScroll could deref NULL amip on SELECTUP.
- get_nhuuid uses ISAAC64 rn2() instead of hand-rolled LCG.
- fopenp's bound check fired one byte too late.
- winami.p had stale signatures for amii_end_menu, amii_select_menu, amii_suspend_nhwindows.

sys/amiga/winami.c

@@ -340,6 +340,11 @@ struct win_setup new_wins[] = {
       22,
       78 },
 
+    /* NHW_PERMINVENT — placeholder; port does not implement persistent
+       inventory yet, but the slot must exist because new_wins[] is
+       indexed by NHW_* type. */
+    { { 0 } },
+
     /* NHW_BASE */
     { { 0, 0, WIDTH, WINDOWHEIGHT, 0xff, 0xff,
         RAWKEY | MENUPICK | MOUSEBUTTONS,