am33xx: Make SoC bootcount driver have its own symbol

Some am33xx boards may not use the RTC block for bootcount (as it may
not be wired up for the board) and use some other facility.  So add
another symbol for the bootcount driver for the IP block.

Acked-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Tom Rini <trini@ti.com>
diff --git a/include/configs/am335x_evm.h b/include/configs/am335x_evm.h
index c2ba7e3..9015927 100644
--- a/include/configs/am335x_evm.h
+++ b/include/configs/am335x_evm.h
@@ -199,6 +199,10 @@
 #define CONFIG_SPL_POWER_SUPPORT
 #define CONFIG_SPL_YMODEM_SUPPORT
 
+/* Bootcount using the RTC block */
+#define CONFIG_BOOTCOUNT_LIMIT
+#define CONFIG_BOOTCOUNT_AM33XX
+
 /* CPSW support */
 #define CONFIG_SPL_ETH_SUPPORT