sdcard: add support for fatfs

examples/sdcard/tinyfs/p1am-100.go

@@ -0,0 +1,17 @@
+// +build p1am_100
+
+package main
+
+import (
+	"machine"
+)
+
+func init() {
+	spi = machine.SDCARD_SPI
+	sckPin = machine.SDCARD_SCK_PIN
+	sdoPin = machine.SDCARD_SDO_PIN
+	sdiPin = machine.SDCARD_SDI_PIN
+	csPin = machine.SDCARD_SS_PIN
+
+	ledPin = machine.LED
+}