[PATCH v3 3/8] cmd: button: add a new 'button' command

[Simon Glass]

Adds a command 'button' that provides the list of buttons
supported by the board, and the state of a button.

Reviewed-by: Simon Glass <sjg at chromium.org>
Signed-off-by: Philippe Reynes <philippe.reynes at softathome.com>
---
Changelog:
v3:
- no change
v2
- no change

 cmd/Kconfig  | 11 ++++++++
 cmd/Makefile |  1 +
 cmd/button.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 98 insertions(+)
 create mode 100644 cmd/button.c

Applied to u-boot-dm, thanks!