Do not match sparc architecture with sparc64-*-* triplet

A sparc64 userland needs a different Debian architecture, as each
GNU triplet should maps 1:1 to a Debian architecture.

cputable

@@ -36,4 +36,4 @@ sh3		sh3		sh3			32	little
 sh3eb		sh3eb		sh3eb			32	big
 sh4		sh4		sh4			32	little
 sh4eb		sh4eb		sh4eb			32	big
-sparc		sparc		sparc(64)?		32	big
+sparc		sparc		sparc			32	big

debian/changelog

@@ -30,6 +30,7 @@ dpkg (1.15.4) UNRELEASED; urgency=low
     package. Closes: #540019
   * Remove double slash in database path visible to the user in some error
     conditions.
+  * Stop macthing sparc64-*-* GNU triplets with sparc Debian architecture.
 
   [ Raphael Hertzog ]
   * Replace install-info by a wrapper around GNU's install-info. The wrapper