env: Add CONFIG_SYS_RELOC_GD_ENV_ADDR symbol

Today in initr_reloc_global_data() we use some non-obvious tests to
determine if we need to relocate the env_addr within gd or not.  In
order to facilitate migration of other symbols to Kconfig we need to
introduce a new symbol for this particular use case.

Cc: Wolfgang Denk <wd@denx.de>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/cobra5272_defconfig b/configs/cobra5272_defconfig
index 8865618..e43f373 100644
--- a/configs/cobra5272_defconfig
+++ b/configs/cobra5272_defconfig
@@ -12,6 +12,7 @@
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_CMD_PING=y
 CONFIG_DEFAULT_DEVICE_TREE="cobra5272"
+CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_MII=y
 CONFIG_BAUDRATE=19200