ppc: Move load and store helpers, switch to AREG0 free mode

Add an explicit CPUPPCState parameter instead of relying on AREG0
and rename op_helper.c (which only contains load and store helpers)
to mem_helper.c. Remove AREG0 swapping in
tlb_fill().

Switch to AREG0 free mode. Use cpu_ld{l,uw}_code in translation
and interrupt handling, cpu_{ld,st}{l,uw}_data in loads and stores.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/configure b/configure
index b68c0ca..6128ba7 100755
--- a/configure
+++ b/configure
@@ -3679,7 +3679,7 @@
 
 
 case "$target_arch2" in
-  alpha | sparc* | xtensa*)
+  alpha | sparc* | xtensa* | ppc*)
     echo "CONFIG_TCG_PASS_AREG0=y" >> $config_target_mak
   ;;
 esac