configure: Drop AIX host support

Nobody has mentioned AIX host support on the mailing list for years,
and we have no test systems for it so it is most likely broken.
We've advertised in configure for two releases now that we plan
to drop support for this host OS, and have had no complaints.
Drop the AIX host support code.

We can also drop the now-unused AIX version of sys_cache_info().

Note that the _CALL_AIX define used in the PPC tcg backend is
also used for Linux PPC64, and so that code should not be removed.

Backports commit 7872375219c03682bda3f6191fa5f6a58238ed36 from qemu

qemu/configure

@@ -172,7 +172,6 @@ bsd="no"
 linux="no"
 solaris="no"
 softmmu="yes"
-aix="no"
 pie=""
 tcg="yes"
 
@@ -446,10 +445,6 @@ SunOS)
   solarisnetlibs="-lsocket -lnsl -lresolv"
   LIBS="$solarisnetlibs $LIBS"
 ;;
-AIX)
-  aix="yes"
-  make="${MAKE-gmake}"
-;;
 Haiku)
   haiku="yes"
   QEMU_CFLAGS="-DB_USE_POSITIVE_POSIX_ERRORS $QEMU_CFLAGS"
@@ -1007,7 +1002,7 @@ elif compile_prog "" "$pthread_lib -lrt" ; then
 fi
 
 if test "$darwin" != "yes" -a "$mingw32" != "yes" -a "$solaris" != yes -a \
-        "$aix" != "yes" -a "$haiku" != "yes" ; then
+        "$haiku" != "yes" ; then
     libs_softmmu="-lutil $libs_softmmu"
 fi
 

qemu/util/cacheinfo.c

@@ -13,16 +13,7 @@
  * Operating system specific detection mechanisms.
  */
 
-#if defined(_AIX)
-# include <sys/systemcfg.h>
-
-static void sys_cache_info(int *isize, int *dsize)
-{
-    *isize = _system_configuration.icache_line;
-    *dsize = _system_configuration.dcache_line;
-}
-
-#elif defined(_WIN32)
+#if defined(_WIN32)
 
 static void sys_cache_info(int *isize, int *dsize)
 {