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/Cubieboard4_defconfig b/configs/Cubieboard4_defconfig
index e44d79e..f83e580 100644
--- a/configs/Cubieboard4_defconfig
+++ b/configs/Cubieboard4_defconfig
@@ -17,5 +17,6 @@
 # CONFIG_SPL_DOS_PARTITION is not set
 # CONFIG_SPL_EFI_PARTITION is not set
 CONFIG_DEFAULT_DEVICE_TREE="sun9i-a80-cubieboard4"
+CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_AXP809_POWER=y
 CONFIG_SYS_USB_EVENT_POLL_VIA_INT_QUEUE=y