Convert CONFIG_SPL_GD_ADDR to Kconfig

This converts the following to Kconfig:
   CONFIG_SPL_GD_ADDR

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/P1020RDB-PC_NAND_defconfig b/configs/P1020RDB-PC_NAND_defconfig
index b49cdcb..6a75d6f 100644
--- a/configs/P1020RDB-PC_NAND_defconfig
+++ b/configs/P1020RDB-PC_NAND_defconfig
@@ -35,6 +35,7 @@
 CONFIG_SPL_FLUSH_IMAGE=y
 CONFIG_SPL_RELOC_TEXT_BASE=0xf8fbe000
 CONFIG_SPL_RELOC_STACK=0xf8fbfff0
+CONFIG_TPL_GD_ADDR=0xf8fac000
 CONFIG_TPL_RELOC_TEXT_BASE=0xf8f81000
 CONFIG_TPL_RELOC_STACK=0xf8fb0000
 CONFIG_TPL_RELOC_MALLOC=y