board: atmel: Use the new PIT timer driver

Use the Atmel PIT timer driver which supports the driver model
and device tree.

Signed-off-by: Wenyou Yang <wenyou.yang@microchip.com>
diff --git a/configs/sama5d3_xplained_nandflash_defconfig b/configs/sama5d3_xplained_nandflash_defconfig
index f3c338c..5539616 100644
--- a/configs/sama5d3_xplained_nandflash_defconfig
+++ b/configs/sama5d3_xplained_nandflash_defconfig
@@ -63,6 +63,9 @@
 CONFIG_DEBUG_UART_BOARD_INIT=y
 CONFIG_DEBUG_UART_ANNOUNCE=y
 CONFIG_ATMEL_USART=y
+CONFIG_TIMER=y
+CONFIG_SPL_TIMER=y
+CONFIG_ATMEL_PIT_TIMER=y
 CONFIG_USB=y
 CONFIG_DM_USB=y
 CONFIG_USB_EHCI_HCD=y