tcg/ppc: Do not overwrite lower address word on Darwin and AIX

For targets where TARGET_LONG_BITS != 32, i.e. 64-bit guests,
addr_reg is moved to r4. For hosts without TCG_TARGET_CALL_ALIGN_ARGS
either data_reg2 or data_reg or a masked version thereof would overwrite
r4. Place it in r5 instead, matching TCG_TARGET_CALL_ALIGN_ARGS hosts.

This fixes immediate crashes of 64-bit guests observed on Darwin/ppc but
not on Darwin/ppc64.
Signed-off-by: NAndreas Färber <andreas.faerber@web.de>
Acked-by: Nmalc <av1474@comtv.ru>
Acked-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

tcg/ppc/tcg-target.c

@@ -816,11 +816,7 @@ static void tcg_out_qemu_st (TCGContext *s, const TCGArg *args, int opc)
 #else
     tcg_out_mov (s, TCG_TYPE_I32, 3, addr_reg2);
     tcg_out_mov (s, TCG_TYPE_I32, 4, addr_reg);
-#ifdef TCG_TARGET_CALL_ALIGN_ARGS
     ir = 5;
-#else
-    ir = 4;
-#endif
 #endif
 
     switch (opc) {