mtd: implement support for LED activity

Implement support for LED activity. If the feature is enabled,
make the defined ACTIVITY LED to signal mtd operations.

LED activity is implemented HERE and not in the subsystem side to limit
any performance degradation in case multiple call to MTD subsystem read/write
are done.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
1 file changed