mediatek: build the boot loader variants in parallel

The variants of arm-trusted-firmware-mediatek and uboot-mediatek only
write to their own build directories and to files in the staging and
bin directories that have the variant in their name.

For the OpenWrt One, a clean build of the 9 TF-A variants takes 2 s
instead of 11 s, and of the 2 U-Boot variants 12 s instead of 21 s.
The images do not change.

Signed-off-by: John Crispin <john@phrozen.org>

package/boot/arm-trusted-firmware-mediatek/Makefile

@@ -16,6 +16,7 @@ PKG_SOURCE_URL=https://github.com/mtk-openwrt/arm-trusted-firmware.git
 PKG_SOURCE_DATE:=2026-01-23
 PKG_SOURCE_VERSION:=e06f258664198a901ff1c7c0c87802a115179451
 PKG_MIRROR_HASH:=e094f5c2838f366e9b2d87e85e0c324ac3b955dd02a493adced843031cf6b517
+PKG_PARALLEL_VARIANTS:=1
 
 PKG_MAINTAINER:=Daniel Golle <daniel@makrotopia.org>
 

package/boot/uboot-mediatek/Makefile

@@ -5,6 +5,7 @@ PKG_VERSION:=2026.07
 PKG_RELEASE:=1
 PKG_HASH:=78e8bfc382fe388f9b55aa1daf8c563522a037779b5d4c349d1415e381f1243e
 PKG_BUILD_DEPENDS:=!(TARGET_ramips||TARGET_mediatek_mt7623):arm-trusted-firmware-tools/host
+PKG_PARALLEL_VARIANTS:=1
 
 ifdef CONFIG_TARGET_ramips
 UBOOT_USE_INTREE_DTC:=1