clocksource: sh_tmu: Set initcall level to subsys

The reason for this is to ensure that TMU is probed earlier
than with its previous initcall level, module init.

This came up as a problem with using CMT as a clock source kzm9g-reference
which does not make use of early timers or devices. In that scenario
initialisation of SDHI and MMCIF both stall on msleep() calls due to the
absence of a initialised clock source.

The purpose of this change is to keep the TMU code in sync with the CMT code
which has been modified in a similar manner..

Boot tested on: mackerel.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

drivers/clocksource/sh_tmu.c

@@ -549,7 +549,7 @@ static void __exit sh_tmu_exit(void)
 }
 
 early_platform_init("earlytimer", &sh_tmu_device_driver);
-module_init(sh_tmu_init);
+subsys_initcall(sh_tmu_init);
 module_exit(sh_tmu_exit);
 
 MODULE_AUTHOR("Magnus Damm");