arm64: dts: librem5-devkit: Hog speaker-mute GPIO

This makes sure the handset speaker is on.
2 jobs for next-devkit in 62 minutes and 27 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
failed #327547
librem5 allowed to fail
build:aarch64

00:15:15

passed #327548
librem5:arm64
build:deb

01:02:27

 
Name Stage Failure
failed
build:aarch64 Build
  CC [M]  drivers/hid/hid-sensor-hub.o
CC [M] drivers/hid/hid-sensor-custom.o
LD [M] drivers/hid/hid-picolcd.o
LD [M] drivers/hid/hid-uclogic.o
LD [M] drivers/hid/wacom.o
AR drivers/hid/built-in.a
LD [M] drivers/hid/hid-wiimote.o
AR drivers/built-in.a
ERROR: Job failed: exit code 1