configure: Do not force pie=no for non-x86

PIE is supported on many other hosts besides x86.

The default for non-x86 is now the same as x86: pie is used
if supported, and may be forced via --enable/--disable-pie.

The original commit (40d6444) said:

  "Non-x86 are not changed, as they require TCG changes"

but I think that's wrong -- there's nothing about PIE that
affects TCG one way or another.

Tested on aarch64 (bionic) and ppc64le (centos 7) hosts.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

configure

@@ -2107,16 +2107,6 @@ if ! compile_prog "-Werror" "" ; then
 	"Thread-Local Storage (TLS). Please upgrade to a version that does."
 fi
 
-if test "$pie" = ""; then
-  case "$cpu-$targetos" in
-    i386-Linux|x86_64-Linux|x32-Linux|i386-OpenBSD|x86_64-OpenBSD)
-      ;;
-    *)
-      pie="no"
-      ;;
-  esac
-fi
-
 if test "$pie" != "no" ; then
   cat > $TMPC << EOF