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/common/touchpad.c

@@ -0,0 +1,20 @@
+#include <board/kbc.h>
+#include <board/touchpad.h>
+#include <common/debug.h>
+#include <ec/ps2.h>
+
+void touchpad_event(void) {
+    if (kbc_second) {
+        *(PS2_TOUCHPAD.control) = 0x07;
+    } else {
+        ps2_reset(&PS2_TOUCHPAD);
+    }
+
+    uint8_t status = *(PS2_TOUCHPAD.status);
+    *(PS2_TOUCHPAD.status) = status;
+    if (status & (1 << 3)) {
+        uint8_t data = *(PS2_TOUCHPAD.data);
+        TRACE("touchpad: %02X\n", data);
+        kbc_mouse(&KBC, data, 1000);
+    }
+}