ath79: add support for TP-Link Archer C2 V3 (AC900)

This commit adds support for the TP-link Archer C2 V3 (AC900).

Specifications:

 - CPU: QCA9563 750Mhz
 - Ram: 64MB (DDR2)
 - Flash: 8MB (SPI NOR)
 - Ethernet: 5x 10/100/1000
 - Wifi: QCA9563 bgn + QCA9887 an+ac
 - 9x Leds, 2x buttons

Flash instructions:

Upload openwrt-ath79-generic-tplink_archer-c2-v3-squashfs-factory.bin
via the router Web interface and flash as normal firmware update.

Signed-off-by: Skirmantas Lauzikas <skirmantas.lauzikas@blackraven.lt>
[reorder entries, fix trailing whitespace in dts, add firmware partition
 compatible string, remove led default off states, use default on state
 for system led, reuse tplink-safeloader-uimage image build recipe, squash
 with dynamic partitioning commit, reword commit message, add
 installation instructions]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

tools/firmware-utils/src/tplink-safeloader.c

@@ -397,6 +397,44 @@ static struct device_info boards[] = {
 		.last_sysupgrade_partition = "file-system",
 	},
 
+	/** Firmware layout for the C2v3 */
+	{
+		.id = "ARCHER-C2-V3",
+		.support_list =
+			"SupportList:\n"
+			"{product_name:ArcherC2,product_ver:3.0.0,special_id:00000000}\n"
+			"{product_name:ArcherC2,product_ver:3.0.0,special_id:55530000}\n"
+			"{product_name:ArcherC2,product_ver:3.0.0,special_id:45550000}\n",
+		.support_trail = '\x00',
+		.soft_ver = "soft_ver:3.0.1\n",
+
+		/** We're using a dynamic kernel/rootfs split here */
+
+		.partitions = {
+			{"factory-boot", 0x00000, 0x20000},
+			{"fs-uboot", 0x20000, 0x10000},
+			{"firmware", 0x30000, 0x7a0000},
+			{"user-config", 0x7d0000, 0x04000},
+			{"default-mac", 0x7e0000, 0x00100},
+			{"device-id", 0x7e0100, 0x00100},
+			{"extra-para", 0x7e0200, 0x00100},
+			{"pin", 0x7e0300, 0x00100},
+			{"support-list", 0x7e0400, 0x00400},
+			{"soft-version", 0x7e0800, 0x00400},
+			{"product-info", 0x7e0c00, 0x01400},
+			{"partition-table", 0x7e2000, 0x01000},
+			{"profile", 0x7e3000, 0x01000},
+			{"default-config", 0x7e4000, 0x04000},
+			{"merge-config", 0x7ec000, 0x02000},
+			{"qos-db", 0x7ee000, 0x02000},
+			{"radio", 0x7f0000, 0x10000},
+			{NULL, 0, 0}
+		},
+
+		.first_sysupgrade_partition = "os-image",
+		.last_sysupgrade_partition = "file-system",
+	},
+
 	/** Firmware layout for the C25v1 */
 	{
 		.id = "ARCHER-C25-V1",