builddeb: Add automatic support for mips{,64}r6{,el} architectures

MIPS R6 is not fully backward-compatible, so Debian has separate
architecture names for userland built for R6.  Label kernel
packages accordingly.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/package/mkdebian

@@ -45,7 +45,9 @@ set_debarch() {
 		debarch=hppa ;;
 	mips*)
 		if is_enabled CPU_LITTLE_ENDIAN; then
-			debarch=mips$(if_enabled_echo 64BIT 64)el
+			debarch=mips$(if_enabled_echo 64BIT 64)$(if_enabled_echo CPU_MIPSR6 r6)el
+		elif is_enabled CPU_MIPSR6; then
+			debarch=mips$(if_enabled_echo 64BIT 64)r6
 		else
 			debarch=mips
 		fi