sh: remove old CMT driver

This patch removes the old CMT driver (CONFIG_SH_CMT/timer-cmt.c)

As replacement, select the sh_cmt driver with CONFIG_SH_TIMER_CMT
and configure timer channel using platform data.

If multiple CMT channels are enabled using platform data, use the
earlytimer parameter on the kernel command line to select channel.
For instance, use "earlytimer=sh_cmt.0" to select the first channel.

To verify which timer is being used, look at printouts or the timer
irq count in /proc/interrupts.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>