ar71xx: add support for RB mAP L-2nD

This patch adds support for the MikroTik RouterBOARD mAP lite
https://routerboard.com/RBmAPL-2nD

Specifications:
- SoC: Qualcomm QCA9533 (650MHz)
- RAM: 64MB
- Storage: 16MB NOR SPI flash
- Wireless: builtin QCA9533, 2x2:2
- Ethernet: 1x100M

This is another 16M SPI NOR mikrotik device. The machine file is named
mach-rbspi.c because I plan to add support for several of the other spi-based
RouterBOARD devices in subsequent patches: they share most of the hardware
and thus the same codebase.

Signed-off-by: Thibaut VARENE <hacks@slashdirt.org>

target/linux/ar71xx/base-files/lib/upgrade/platform.sh

@@ -344,6 +344,7 @@ platform_check_image() {
 	pb42|\
 	pb44|\
 	rb-941-2nd|\
+	rb-mapl-2nd|\
 	routerstation-pro|\
 	routerstation|\
 	wp543|\
@@ -615,7 +616,8 @@ platform_pre_upgrade() {
 	local board=$(ar71xx_board_name)
 
 	case "$board" in
-	rb-941-2nd)
+	rb-941-2nd|\
+	rb-mapl-2nd)
 		;;
 	rb*|\
 	c-60|\
@@ -651,7 +653,8 @@ platform_do_upgrade() {
 	local board=$(ar71xx_board_name)
 
 	case "$board" in
-	rb-941-2nd)
+	rb-941-2nd|\
+	rb-mapl-2nd)
 		PLATFORM_DO_UPGRADE_COMBINED_SEPARATE_MTD=1
 		platform_do_upgrade_combined "$ARGV"
 		;;