clk: ingenic-tcu: Fix missing TCU clock for X1000 SoCs

The TCU clock gate on X1000 wasn't requested by the driver and could
be gated automatically later on in boot, which prevents timers from
running and breaks PWM.

Add a workaround to support old device trees that don't specify the
"tcu" clock gate. In this case the kernel will print a warning and
attempt to continue without the clock, which is wrong, but it could
work if "clk_ignore_unused" is in the kernel arguments.

Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@gmail.com>
Link: https://lore.kernel.org/r/20220412122750.279058-3-aidanmacdonald.0x0@gmail.com


Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>