System76 common board directory (#53)

* Move configuration for battery into board.mk

* lemp9: remove tcpm code

* Move touchpad to its own module

* Add kbled_reset to all platforms, move items to run on CPU reset to a function

* Add defines for battery and charger address

* Add I2C_0 export to it5570e

* Move common system76 board functions into src/board/system76/common

src/board/system76/lemp9/board.c

@@ -0,0 +1,21 @@
+#include <board/board.h>
+#include <board/gctrl.h>
+#include <board/gpio.h>
+#include <board/power.h>
+
+extern uint8_t main_cycle;
+
+void board_init(void) {
+    RSTS = 0x44;
+}
+
+void board_event(void) {
+    if (main_cycle == 0) {
+        if (power_state == POWER_STATE_S0 || power_state == POWER_STATE_S3 || power_state == POWER_STATE_DS3) {
+            // System is on
+        } else if (gpio_get(&ACIN_N)) {
+            // Power off VDD3 if system should be off
+            gpio_set(&XLP_OUT, 0);
+        }
+    }
+}