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/ds414_defconfig b/configs/ds414_defconfig
index 9114fed..bc0446d 100644
--- a/configs/ds414_defconfig
+++ b/configs/ds414_defconfig
@@ -45,6 +45,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="armada-xp-synology-ds414"
 CONFIG_USE_ENV_SPI_MAX_HZ=y
 CONFIG_ENV_SPI_MAX_HZ=50000000
+CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_NET_RANDOM_ETHADDR=y
 CONFIG_SPL_OF_TRANSLATE=y
 CONFIG_BLK=y