siemens: add led cmd for flexible LED control
* remove setting LED in user button function.
We want to decouple reading user button and setting LED. This
two things need to be done independently.
* led cmd can be used to control LEDs that are defined in board file
having a led cmd, one can easily set LEDs in u-boot shell. For
example bootcmd can be extended to disable status LED before
loading kernel.
Signed-off-by: Samuel Egli <[email protected]>
Cc: Roger Meier <[email protected]>
Cc: Heiko Schocher <[email protected]>
Cc: Wolfgang Denk <[email protected]>