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/MK808C_defconfig b/configs/MK808C_defconfig
index 7f23f9e..3a07deb 100644
--- a/configs/MK808C_defconfig
+++ b/configs/MK808C_defconfig
@@ -11,6 +11,7 @@
 # CONFIG_SPL_DOS_PARTITION is not set
 # CONFIG_SPL_EFI_PARTITION is not set
 CONFIG_DEFAULT_DEVICE_TREE="sun7i-a20-mk808c"
+CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_OHCI_HCD=y
 CONFIG_SYS_USB_EVENT_POLL_VIA_INT_QUEUE=y