add sparc64-softmmu to default configure targets list

Add sparc64 to default list of softmmu targets
Signed-off-by: NIgor V. Kovalenko <igor.v.kovalenko@gmail.com>

configure

@@ -714,6 +714,7 @@ ppc64-softmmu \
 sh4-softmmu \
 sh4eb-softmmu \
 sparc-softmmu \
+sparc64-softmmu \
 "
     fi
 # the following are Linux specific