Migrate generic bootcount to Kconfig

Make generate boot counter selected in the same way as other boot count
drivers

Reviewed-by: Lukasz Majewski <lukma@denx.de>
Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
diff --git a/drivers/bootcount/Kconfig b/drivers/bootcount/Kconfig
index e0d1fc2..9fde2f2 100644
--- a/drivers/bootcount/Kconfig
+++ b/drivers/bootcount/Kconfig
@@ -14,6 +14,16 @@
 	prompt "Boot count device"
 	default BOOTCOUNT_AM33XX if AM33XX || SOC_DA8XX
 	default BOOTCOUNT_AT91 if AT91SAM9XE
+	default BOOTCOUNT_GENERIC
+
+config BOOTCOUNT_GENERIC
+	bool "Generic default boot counter"
+	help
+	  Generic bootcount stored at SYS_BOOTCOUNT_ADDR.
+
+	  SYS_BOOTCOUNT_ADDR:
+	    Set to the address where the bootcount and bootcount magic
+	    will be stored.
 
 config BOOTCOUNT_EXT
 	bool "Boot counter on EXT filesystem"
@@ -64,6 +74,7 @@
 
 config SYS_BOOTCOUNT_SINGLEWORD
 	bool "Use single word to pack boot count and magic value"
+	depends on BOOTCOUNT_GENERIC
 	help
 	  This option enables packing boot count magic value and boot count
 	  into single word (32 bits).