Convert CONFIG_BOOTCOUNT_RAM to Kconfig

This converts the following to Kconfig:
  CONFIG_BOOTCOUNT_RAM

Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
diff --git a/configs/mgcoge3un_defconfig b/configs/mgcoge3un_defconfig
index 5c0946a..6a96b62 100644
--- a/configs/mgcoge3un_defconfig
+++ b/configs/mgcoge3un_defconfig
@@ -30,6 +30,7 @@
 CONFIG_BOOTP_GATEWAY=y
 CONFIG_BOOTP_HOSTNAME=y
 CONFIG_BOOTCOUNT_LIMIT=y
+CONFIG_BOOTCOUNT_RAM=y
 # CONFIG_MMC is not set
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_STMICRO=y