Migrate CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC

This converts CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC to Kconfig

Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
diff --git a/drivers/bootcount/Kconfig b/drivers/bootcount/Kconfig
index 73972b7..d335ed1 100644
--- a/drivers/bootcount/Kconfig
+++ b/drivers/bootcount/Kconfig
@@ -34,6 +34,7 @@
 config BOOTCOUNT_AM33XX
 	bool "Boot counter in AM33XX RTC IP block"
 	depends on AM33XX || SOC_DA8XX
+	select SPL_AM33XX_ENABLE_RTC32K_OSC if AM33XX
 	help
 	  A bootcount driver for the RTC IP block found on many TI platforms.
 	  This requires the RTC clocks, etc, to be enabled prior to use and