tcg: pointer size warning on x32 arch

[Michael Tokarev]

Hi.

The following warning is reported by the C compiler when compiling
tcg code on x32 architecture:

In file included from ../../tcg/tcg.c:429:
tcg/i386/tcg-target.c.inc: In function ‘tcg_out_movi_int’:
tcg/i386/tcg-target.c.inc:959:30: warning: cast to pointer from integer of 
different size [-Wint-to-pointer-cast]
  959 |     diff = tcg_pcrel_diff(s, (const void *)arg) - 7;

I dunno if we should be concerned or if it is worth to support x32
in the first place. But I thought I'd report it anyway.

Thanks!

/mjt