Commit 8b2104d740 ("driver: Call of_clk_set_defaults for each probed device")
made barebox act on the assigned-clock-parents property everywhere, not
only for clock provider nodes. This breaks at least the serial console on
the i.MX7 SabreSD board; only garbage is output if the patch is not
reverted. As stopgap measure, override these properties for all enabled
uart nodes in the barebox i.MX7 device tree. This reverts the behavior
to what it was like before the offending commit.

This is of course no real solution, as obviously Linux was fine dealing
with these properties before. But this hack should at least fix the
serial console for the boards that were broken in v2020.03.0.

When a proper fix follows, this patch can be reverted.

Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Juergen Borleis <jbe@pengutronix.de>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>