Add support for FOXNEO FNS-1200P (RTL8372, 4x2.5G PoE+ + 2x SFP+)

- machine.c/h: add MACHINE_FNS1200P with verified GPIO assignments for
  both SFP ports, LED SET0 (amber 2.5G / green 1G-100M-10M) and SET1
  (SFP all-speeds), led_mux from original firmware register dump, and
  machine_custom_init() enabling LED_GLB_IO_EN bit 6
- doc/devices/FNS-1200P.md: device overview, port layout, serial
  console (S1 three through-holes = UART0 115200 8N1 3.3V),
  LED and SFP GPIO tables
- doc/devices/photos/FNS-1200P/: chassis front panel and PCB top photos
- doc/supported_devices.md: add FNS-1200P to the list

GPIO assignments and LED register values were cross-checked between
live GPIO observation (RTLPlayground gpio command) and an original
firmware register dump.

machine.c

@@ -666,6 +666,66 @@ __code const struct machine machine = {
 
 void machine_custom_init(void) { }
 
+#elif defined MACHINE_FNS1200P
+__code const struct machine machine = {
+    .machine_name = "FNS-1200P",
+    .isRTL8373 = 0,
+    .min_port = 3,
+    .max_port = 8,
+    .n_sfp = 2,
+    .log_to_phys_port = {0, 0, 0, 6, 1, 2, 3, 4, 5},
+    .phys_to_log_port = {4, 5, 6, 7, 8, 3, 0, 0, 0},
+    .is_sfp = {0, 0, 0, 2, 0, 0, 0, 0, 1},
+
+    /* Left SFP (logical 8, SDS1): GPIO30=ModAbs, GPIO37=RX_LOS */
+    .sfp_port[0].pin_detect = GPIO30_ACL_BIT3_EN,
+    .sfp_port[0].pin_los = GPIO37,
+    .sfp_port[0].pin_tx_disable = GPIO_NA,
+    .sfp_port[0].sds = 1,
+    .sfp_port[0].i2c = { .sda = GPIO39_I2C_SDA4, .scl = GPIO40_I2C_SCL3_MDC1 },
+
+    /* Right SFP (logical 3, SDS0): GPIO50=ModAbs, GPIO51=RX_LOS */
+    .sfp_port[1].pin_detect = GPIO50_I2C_SCL2_UART1_TX,
+    .sfp_port[1].pin_los = GPIO51_I2C_SDA2_UART1_RX,
+    .sfp_port[1].pin_tx_disable = GPIO_NA,
+    .sfp_port[1].sds = 0,
+    .sfp_port[1].i2c = { .sda = GPIO41_I2C_SDA3_MDIO1, .scl = GPIO40_I2C_SCL3_MDC1 },
+
+    .reset_pin = GPIO_NA,
+
+    .high_leds = { .mux = LED_27 | LED_28_SYS | LED_29, .enable = LED_28_SYS | LED_29 },
+
+    /* Copper ports use SET0; SFP ports use SET1 */
+    .port_led_set = {0, 0, 0, 1, 0, 0, 0, 0, 1},
+
+    .led_sets = {
+        {   /* SET0: copper — LED0=amber (2.5G), LED2=green (1G/100M/10M) */
+            LEDS_2G5 | LEDS_LINK | LEDS_ACT,
+            0,
+            LEDS_1G | LEDS_100M | LEDS_10M | LEDS_LINK | LEDS_ACT,
+            0
+        },
+        {   /* SET1: SFP — all speeds link/act */
+            LEDS_10G | LEDS_2G5 | LEDS_1G | LEDS_100M | LEDS_10M | LEDS_LINK | LEDS_ACT,
+            0,
+            0, 0
+        },
+    },
+
+    .led_mux_custom = 1,
+    .led_mux = {
+        0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f, 0x3f,  /* GPIO0-7: unused */
+        0x0f, 0x0c, 0x0d, 0x0e, 0x10, 0x11, 0x12,          /* GPIO8-14 */
+        0x14, 0x15, 0x16, 0x18, 0x19, 0x1a,                 /* GPIO15-20 */
+        0x1c, 0x1d, 0x1e, 0x20, 0x21, 0x22, 0x23            /* GPIO21-27 */
+    },
+};
+
+void machine_custom_init(void)
+{
+    reg_bit_set(RTL837X_REG_LED_GLB_IO_EN, 6);
+}
+
 #else
 	#error "Please select a machine type in machine.h"
 #endif