PPC: Fix compilation with TCG debug

The recent VSX patches broken compilation of QEMU when configurated
with --enable-debug, as it was treating "target long" TCG variables
as "i64" which is not true for 32bit targets.

This patch fixes all the places that the compiler has found to use
the correct variable type and if necessary manually cast.

Reported-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>