sdcard: remove tinyfs example and replace with link to tinyfs repo in docs

Signed-off-by: deadprogram <ron@hybridgroup.com>

sdcard/README.md

@@ -1,8 +1,14 @@
 # SPI sdcard/mmc driver
 
-This package provides the driver for sdcard/mmc with SPI connection.  
-`examples/sdcard/console` shows a low-level access example.  
-`examples/sdcard/tinyfs` shows an example of using fatfs to read FAT32.  
+This package provides the driver for sdcard/mmc with SPI connection.
+
+To use a file system on the SDcard, please see the TinyFS repo:
+
+https://github.com/tinygo-org/tinyfs
+
+See `examples/sdcard/console` for a low-level access example.
+
+## Stack size
 
 If you use this package, you need to set `default-stack-size` in `targets/*.json`.  
 For example, `targets/wioterminal.json` has the following configuration.  

sdcard/sdcard.go

@@ -1,3 +1,9 @@
+// package sdcard provides a TinyGo driver for sdcard/mmc devices
+// using a SPI connection.
+//
+// To use a file system on the SDcard, please see the TinyFS repo:
+//
+// https://github.com/tinygo-org/tinyfs
 package sdcard
 
 import (