sunxi: add gmac Ethernet support

Add support for the GMAC Ethernet controller on Allwinner A20 (sun7i)
processors. Enable for the Cubietruck.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Jens Kuske <jenskuske@gmail.com>
Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Reviewed-by: Marek Vasut <marex@denx.de>
Reviewed-by: Tom Rini <trini@ti.com>
diff --git a/boards.cfg b/boards.cfg
index db3a6ae..bc05030 100644
--- a/boards.cfg
+++ b/boards.cfg
@@ -379,7 +379,7 @@
 Active  arm         armv7          s5pc1xx     samsung         goni                s5p_goni                              -                                                                                                                                 Przemyslaw Marczak <p.marczak@samsung.com>
 Active  arm         armv7          s5pc1xx     samsung         smdkc100            smdkc100                              -                                                                                                                                 Minkyu Kang <mk7.kang@samsung.com>
 Active  arm         armv7          socfpga     altera          socfpga             socfpga_cyclone5                      -                                                                                                                                 -
-Active  arm         armv7          sunxi       -               sunxi               Cubietruck_FEL                        sun7i:CUBIETRUCK,SPL_FEL                                                                                                          -
+Active  arm         armv7          sunxi       -               sunxi               Cubietruck_FEL                        sun7i:CUBIETRUCK,SPL_FEL,SUNXI_GMAC,RGMII                                                                                         -
 Active  arm         armv7          u8500       st-ericsson     snowball            snowball                              -                                                                                                                                 Mathieu Poirier <mathieu.poirier@linaro.org>
 Active  arm         armv7          u8500       st-ericsson     u8500               u8500_href                            -                                                                                                                                 -
 Active  arm         armv7          vf610       freescale       vf610twr            vf610twr                              vf610twr:IMX_CONFIG=board/freescale/vf610twr/imximage.cfg                                                                         Alison Wang <b18965@freescale.com>