clocksource: sh_cmt: Initialize 'max_match_value' and 'lock' in sh_cmt_setup()

Move the setup of spinlock and max_match_value to sh_cmt_setup().
There's no need to defer those steps until sh_cmt_register().

Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Magnus Damm <damm@opensource.se>
Acked-by: John Stultz <john.stultz@linaro.org>
Tested-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>