input: specialkeys: remove unused printk argument ...

Two pr_info calls have no format specifiers, but are still passed an
argument. Remove the unused arguments.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

input: add handler for reset and power key input events ...

Kernel device trees may indicate linux,code = KEY_POWER or KEY_RESTART,
mostly for gpio-keys. Make barebox able to act on them by registering an
appropriate input notifier.

Suggested-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>