nanopi-r76s: bump mainline u-boot to v2026.04 and drop vendor-branch gates (#9869)

* nanopi-r76s: bump mainline u-boot to v2026.04 and drop vendor-branch gates

Drop the BRANCH==vendor early-returns in both
post_family_config__nanopi_r76s_use_mainline_uboot and
pre_config_uboot_target__nanopi_r76s_patch_rockchip_common_boot_order
so mainline u-boot is taken on every kernel branch, and bump
BOOTBRANCH/BOOTPATCHDIR from v2026.01 to v2026.04.  The R76S board
support patch is still carried locally since the board is not yet
in u-boot upstream.

Signed-off-by: SuperKali <hello@superkali.me>

* nanopi-r76s: refresh u-boot v2026.04 patch and flip boot order

Reformat board support patch with proper format-patch headers, set
mmc1 (SD) before mmc0 (eMMC) to match upstream Linux DTS aliases.

---------

Signed-off-by: SuperKali <hello@superkali.me>

Author: SuperKali

config/boards/nanopi-r76s.conf

@@ -23,15 +23,12 @@ function post_family_tweaks__nanopi-r76s_naming_audios() {
 }
 
 function post_family_config__nanopi_r76s_use_mainline_uboot() {
-	# Use mainline U-Boot for edge, keep vendor U-Boot for vendor branch
-	[[ "${BRANCH}" == "vendor" ]] && return 0
-
 	display_alert "$BOARD" "Using mainline U-Boot for $BOARD / $BRANCH" "info"
 
 	declare -g BOOTDELAY=1
 	declare -g BOOTSOURCE="https://github.com/u-boot/u-boot.git"
-	declare -g BOOTBRANCH="tag:v2026.01"
-	declare -g BOOTPATCHDIR="v2026.01"
+	declare -g BOOTBRANCH="tag:v2026.04"
+	declare -g BOOTPATCHDIR="v2026.04"
 	unset BOOT_FDT_FILE
 
 	# Don't set BOOTDIR, allow shared U-Boot source directory for disk space efficiency
@@ -46,15 +43,10 @@ function post_family_config__nanopi_r76s_use_mainline_uboot() {
 	}
 }
 
-# "rockchip-common: boot SD card first, then NVMe, then mmc"
-# include/configs/rockchip-common.h
-# -#define BOOT_TARGETS "mmc1 mmc0 nvme scsi usb pxe dhcp"
-# +#define BOOT_TARGETS "mmc0 mmc1 nvme scsi usb pxe dhcp"
-# On NanoPi R76S, mmc0 is the SD card, mmc1 is the eMMC slot
+# Upstream Linux DTS aliases: mmc0 = &sdhci (eMMC), mmc1 = &sdmmc (SD), mmc2 = &sdio
+# Boot SD first, then eMMC, then NVMe
 function pre_config_uboot_target__nanopi_r76s_patch_rockchip_common_boot_order() {
-	[[ "${BRANCH}" == "vendor" ]] && return 0
-
-	declare -a rockchip_uboot_targets=("mmc0" "mmc1" "nvme" "scsi" "usb" "pxe" "dhcp") # for future make-this-generic delight
+	declare -a rockchip_uboot_targets=("mmc1" "mmc0" "nvme" "scsi" "usb" "pxe" "dhcp")
 	display_alert "u-boot for ${BOARD}/${BRANCH}" "u-boot: adjust boot order to '${rockchip_uboot_targets[*]}'" "info"
 	sed -i -e "s/#define BOOT_TARGETS.*/#define BOOT_TARGETS \"${rockchip_uboot_targets[*]}\"/" include/configs/rockchip-common.h
 	regular_git diff -u include/configs/rockchip-common.h || true