[RS6000] gcc/configure typo fix

[Alan Modra via Gcc-patches]

Committed as obvious.

        * configure.ac (--with-long-double-format): Typo fix.
        * configure: Regenerate.

diff --git a/gcc/configure.ac b/gcc/configure.ac
index f5612161dcd..1ad5bbc6935 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -6260,7 +6260,7 @@ supported if the default cpu is power7 or newer])
        ;;
       esac
       ;;
-  xpowerpc64*-*-linux*:*)
+  powerpc64*-*-linux*:*)
     AC_MSG_ERROR([--with-long-double-format argument should be ibm or ieee])
     with_long_double_format=""
     ;;

-- 
Alan Modra
Australia Development Lab, IBM