BCM27XX_DT: Delete 'stdout-path' property

BCM27XX_DT: Delete 'stdout-path' property

The 'stdout-path' property introduced upstream changes the behaviour
on a non-Bluetooth Pi by enabling a console on UART0 when the user
may not want one. The boot order is such that /dev/console ends up
on the serial port instead of tty0.

Delete the property in downstream DTBs to retrurn to the previous
behaviour of only enabling consoles selected in cmdline.txt.

See: https://github.com/raspberrypi/linux/issues/2436

Signed-off-by: Phil Elwell <phil@raspberrypi.org>
(cherry picked from commit a69c920f22883371042de9bb53d84e15f7818197
https://github.com/raspberrypi/linux raspi/rpi-4.15.y)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>