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/socrates_defconfig b/configs/socrates_defconfig
index cd04e0e..ed54d3d 100644
--- a/configs/socrates_defconfig
+++ b/configs/socrates_defconfig
@@ -7,6 +7,7 @@
 CONFIG_ENV_ADDR=0xFFF40000
 # CONFIG_SYS_PCI_64BIT is not set
 CONFIG_MPC85xx=y
+CONFIG_SYS_INIT_RAM_LOCK=y
 # CONFIG_CMD_ERRATA is not set
 CONFIG_TARGET_SOCRATES=y
 CONFIG_ENABLE_36BIT_PHYS=y