timer: atmel_tcb_timer: add atmel_tcb driver

Add a driver for the timer counter block that can be found on sama5d2.
This driver will be used when booting under OP-TEE since the pit timer
which is part of the SYSC is secured. Channel 1 & 2 are configured to
be chained together which allows to have a 64bits counter.

Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Clément Léger <clement.leger@bootlin.com>

drivers/timer/Kconfig

@@ -96,6 +96,14 @@ config ATMEL_PIT_TIMER
 	  it is designed to offer maximum accuracy and efficient management,
 	  even for systems with long response time.
 
+config ATMEL_TCB_TIMER
+	bool "Atmel timer counter support"
+	depends on TIMER
+	depends on ARCH_AT91
+	help
+	  Select this to enable the use of the timer counter as a monotonic
+	  counter.
+
 config CADENCE_TTC_TIMER
 	bool "Cadence TTC (Triple Timer Counter)"
 	depends on TIMER