Applied suggestions from review

Removed reference to 'MTD_0', fixed formatting and failed static test for trailing whitespaces

examples/filesystem/README.md

@@ -8,19 +8,17 @@ application.
 In particular, this example shows:
 
 - how to mount/format/unmount a file system, either with constfs for all
-  devices and the default fs for devices that have a filesystem mountpoint configured by the board.
+  devices and the default fs for devices that have a filesystem mountpoint
+  configured by the board.
 - how to open/read/write/close a file with and without newlib
 
 A `constfs` file system is demonstrated with two files for all targets
 to demonstrate the file system functionality without an external mass
 storage device.
 
-For targets that feature an onboard external mass storage device with a mount point configured, like
-the Nordic nRF52840 Development Kit (see `boards/nrf52840dk`), the 
-flash chip is automatically added by VFS.
-In RIOT, most file systems use a `mtd` as flash interface. So to use this
-example the define `MTD_0` must exist. `MTD_0` is a pointer to a 
-`mtd_dev_t` instance. 
+For targets that feature an onboard external mass storage device with a 
+mount point configured, like the Nordic nRF52840 Development Kit 
+(see `boards/nrf52840dk`), the flash chip is automatically added by VFS.
 
 This example uses `littlefs` as default file system on the whole `mtd`.