builddeb: Drop check for 32-bit s390

s390 now only supports 64-bit configurations.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/package/mkdebian

@@ -21,7 +21,7 @@ set_debarch() {
 	sparc*)
 		debarch=sparc ;;
 	s390*)
-		debarch=s390$(grep -q CONFIG_64BIT=y $KCONFIG_CONFIG && echo x || true) ;;
+		debarch=s390x ;;
 	ppc*)
 		debarch=$(grep -q CPU_LITTLE_ENDIAN=y $KCONFIG_CONFIG && echo ppc64el || echo powerpc) ;;
 	parisc*)