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/stdio.c

@@ -0,0 +1,30 @@
+#include <stdio.h>
+
+#include <board/smfi.h>
+
+#ifdef SERIAL_DEBUGGER
+    #include <mcs51/8051.h>
+#endif
+
+#ifdef I2C_DEBUGGER
+    #include <ec/i2c.h>
+#endif
+
+#ifdef PARPORT_DEBUG
+    #include <ec/parallel.h>
+#endif
+
+int putchar(int c) {
+    unsigned char byte = (unsigned char)c;
+    smfi_debug(byte);
+#ifdef SERIAL_DEBUGGER
+    SBUF = byte;
+#endif
+#ifdef I2C_DEBUGGER
+    i2c_send(&I2C_SMBUS, I2C_DEBUGGER, &byte, 1);
+#endif
+#ifdef PARPORT_DEBUG
+    parport_write(&byte, 1);
+#endif
+    return (int)byte;
+}