clocksource: ingenic: Add explicit include for cpuhotplug.h

Removing include of cpu.h from of_device.h (included by of_platform.h)
causes an error in ingenic-timer:

drivers/clocksource/ingenic-timer.c: In function ‘ingenic_tcu_init’:
drivers/clocksource/ingenic-timer.c:338:15: error: implicit declaration of function ‘cpuhp_setup_state’

The of_platform.h header is not necessary either, so it and of_address.h
can be dropped.

Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230329-dt-cpu-header-cleanups-v1-11-581e2605fe47@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/clocksource/ingenic-timer.c

@@ -9,13 +9,12 @@
 #include <linux/clk.h>
 #include <linux/clockchips.h>
 #include <linux/clocksource.h>
+#include <linux/cpuhotplug.h>
 #include <linux/interrupt.h>
 #include <linux/mfd/ingenic-tcu.h>
 #include <linux/mfd/syscon.h>
 #include <linux/of.h>
-#include <linux/of_address.h>
 #include <linux/of_irq.h>
-#include <linux/of_platform.h>
 #include <linux/overflow.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>