Convert CONFIG_BOOTCOUNT_LIMIT to Kconfig

This converts the following to Kconfig:
   CONFIG_BOOTCOUNT_LIMIT

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Tested-by: Alex Kiernan <alex.kiernan@gmail.com>
Reviewed-by: Hannes Schmelzer <hannes.schmelzer@br-automation.com>
Acked-by: Hannes Schmelzer <hannes.schmelzer@br-automation.com>
diff --git a/drivers/bootcount/Kconfig b/drivers/bootcount/Kconfig
index c9d627c..cb6be73 100644
--- a/drivers/bootcount/Kconfig
+++ b/drivers/bootcount/Kconfig
@@ -11,6 +11,12 @@
 	  number of times the board has booted on a number of different
 	  persistent storage mediums.
 
+config BOOTCOUNT_LIMIT
+	bool "Enable support for checking boot count limit"
+	help
+	  Enable checking for exceeding the boot count limit.
+	  More information: http://www.denx.de/wiki/DULG/UBootBootCountLimit
+
 if BOOTCOUNT
 
 config BOOTCOUNT_EXT