hw/timer: RX62N compare match timer (CMT)

hw/timer: RX62N compare match timer (CMT)

renesas_cmt: 16bit compare match timer modules.
This part use many renesas's CPU.
Hardware manual.
https://www.renesas.com/us/en/doc/products/mpumcu/doc/rx_family/r01uh0033ej0140_rx62n.pdf

Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20200224141923.82118-16-ysato@users.sourceforge.jp>
[PMD: Split from TMR, filled VMStateField for migration]
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>