sunxi: Fix CONFIG_SUNXI_GMAC references

SUNXI_GMAC was still used to configure the code where as the
same has been renamed and moved to Kconfig in below commit
"sunxi: Move SUNXI_GMAC to Kconfig"
(sha1: 4d43d065db3262f9a9918ba72457bf36dfb8e0bb)

Signed-off-by: Dave Prue <dave@prue.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagan Teki <jagan@openedev.com>
Reviewed-by: Mark Kettenis <kettenis@openbsd.org>
Tested-by: Mark Kettenis <kettenis@openbsd.org>
[Tweek commit message, config_whitelist.txt, build-whitelist.sh]
Signed-off-by: Jagan Teki <jagan@openedev.com>
diff --git a/board/sunxi/Makefile b/board/sunxi/Makefile
index f4411f0..526cb72 100644
--- a/board/sunxi/Makefile
+++ b/board/sunxi/Makefile
@@ -9,7 +9,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 obj-y	+= board.o
-obj-$(CONFIG_SUNXI_GMAC)	+= gmac.o
+obj-$(CONFIG_SUN7I_GMAC)	+= gmac.o
 ifndef CONFIG_SPL_BUILD
 obj-$(CONFIG_SUNXI_AHCI)	+= ahci.o
 endif