This beeper hardware requires a PWM driver for frequency selection.
Since the GPIO driver does not provide that, revert the beeper
support to a simple gpio-export.
This effectively reverts the corresponding changes from
6ba58b7b020c ("ramips: cleanup the RB750Gr3 support")
Signed-off-by: John Thomson <git@johnthomson.fastmail.com.au>
[commit title/message facelift]
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Signed-off-by: maurerr <mariusd84@gmail.com>
7821bba8b9