Convert CONFIG_SYS_INIT_RAM_LOCK to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_INIT_RAM_LOCK

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/tuxx1_defconfig b/configs/tuxx1_defconfig
index 3711d22..da408e4 100644
--- a/configs/tuxx1_defconfig
+++ b/configs/tuxx1_defconfig
@@ -9,6 +9,7 @@
 CONFIG_ENV_ADDR=0xF00C0000
 CONFIG_MPC83xx=y
 CONFIG_HIGH_BATS=y
+CONFIG_SYS_INIT_RAM_LOCK=y
 CONFIG_TARGET_TUXX1=y
 CONFIG_CORE_PLL_RATIO_25_1=y
 CONFIG_QUICC_MULT_FACTOR_3=y