timers: atmel_tcb: introduce CONFIG_SPL_ATMEL_TCB

This commit allows the ATMEL_TCB driver to be unselected in SPL and be
selected in u-boot proper. The SPL can use a different timer.
By having a separate Kconfig for ATMEL_TCB in SPL, the size of the SPL
decreases by 1 KByte.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig
index 672746a..68e90b8 100644
--- a/drivers/timer/Kconfig
+++ b/drivers/timer/Kconfig
@@ -98,6 +98,14 @@
 	  Select this to enable the use of the timer counter as a monotonic
 	  counter.
 
+config SPL_ATMEL_TCB_TIMER
+	bool "Atmel timer counter support in SPL"
+	depends on SPL_TIMER
+	depends on ARCH_AT91
+	help
+	  Select this to enable the use of the timer counter as a monotonic
+	  counter in SPL.
+
 config CADENCE_TTC_TIMER
 	bool "Cadence TTC (Triple Timer Counter)"
 	depends on TIMER