timers: atmel_pit: introduce CONFIG_SPL_ATMEL_PIT_TIMER

This commit allows the ATMEL_PIT_TIMER 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 0.3 KBytes.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
diff --git a/drivers/timer/Makefile b/drivers/timer/Makefile
index ae01a25..35cc490 100644
--- a/drivers/timer/Makefile
+++ b/drivers/timer/Makefile
@@ -7,7 +7,8 @@
 obj-$(CONFIG_ANDES_PLMT_TIMER) += andes_plmt_timer.o
 obj-$(CONFIG_ARC_TIMER)	+= arc_timer.o
 obj-$(CONFIG_AST_TIMER)	+= ast_timer.o
-obj-$(CONFIG_ATMEL_PIT_TIMER) += atmel_pit_timer.o
+obj-$(CONFIG_ATCPIT100_TIMER) += atcpit100_timer.o
+obj-$(CONFIG_$(SPL_)ATMEL_PIT_TIMER) += atmel_pit_timer.o
 obj-$(CONFIG_$(SPL_)ATMEL_TCB_TIMER) += atmel_tcb_timer.o
 obj-$(CONFIG_CADENCE_TTC_TIMER)	+= cadence-ttc.o
 obj-$(CONFIG_DESIGNWARE_APB_TIMER)	+= dw-apb-timer.o