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/MSI_Primo81_defconfig b/configs/MSI_Primo81_defconfig
index 12f8bd9..b21ec29 100644
--- a/configs/MSI_Primo81_defconfig
+++ b/configs/MSI_Primo81_defconfig
@@ -18,6 +18,7 @@
 # CONFIG_SPL_DOS_PARTITION is not set
 # CONFIG_SPL_EFI_PARTITION is not set
 CONFIG_DEFAULT_DEVICE_TREE="sun6i-a31s-primo81"
+CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_AXP_DLDO1_VOLT=3300
 # CONFIG_REQUIRE_SERIAL_CONSOLE is not set
 CONFIG_USB_MUSB_HOST=y