builddeb: Add automatic support for riscv* architectures

Debian currently only defines "riscv64", but it seems safe to assume
that any 32-bit port will now be called "riscv32", also matching
$UTS_MACHINE.
Signed-off-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

scripts/package/mkdebian

@@ -26,7 +26,7 @@ set_debarch() {
 
 	# Attempt to find the correct Debian architecture
 	case "$UTS_MACHINE" in
-	i386|ia64|alpha|m68k)
+	i386|ia64|alpha|m68k|riscv*)
 		debarch="$UTS_MACHINE" ;;
 	x86_64)
 		debarch=amd64 ;;