builddeb: Add automatic support for mips64el architecture

We currently label 64-bit little-endian kernel packages as
mipsel (32-bit little-endian), mostly it was officially supported
while mips64el (64-bit little-endian) was not.  Now both are
officially supported, so label these packages as mips64el.
Signed-off-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

scripts/package/mkdebian

@@ -44,7 +44,12 @@ set_debarch() {
 	parisc*)
 		debarch=hppa ;;
 	mips*)
-		debarch=mips$(if_enabled_echo CPU_LITTLE_ENDIAN el) ;;
+		if is_enabled CPU_LITTLE_ENDIAN; then
+			debarch=mips$(if_enabled_echo 64BIT 64)el
+		else
+			debarch=mips
+		fi
+		;;
 	aarch64|arm64)
 		debarch=arm64 ;;
 	arm*)