sun7i: a20: Add Bananapi M1 Plus support

Banana Pi M1 Plus is an open-source single-board computer
that adds more connectivity to the classic board using
Allwinner A20 SOC.

Bananapi M1-Plus features:
- A20 Dual-core 1.0GHz
- 1 GB DDR3 SDRAM
- MicroSD
- 10/100/1000 Ethernet RJ45
- WiFi b/g/n
- 5V DC Micro USB power-supply

For dts file,
Sync with Linux commit f92ca09("Merge branch 'akpm/master'").

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>

configs/bananapi_m1_plus_defconfig

@@ -0,0 +1,24 @@
+CONFIG_ARM=y
+CONFIG_ARCH_SUNXI=y
+CONFIG_MACH_SUN7I=y
+CONFIG_DRAM_CLK=432
+CONFIG_MACPWR="PH23"
+CONFIG_VIDEO_COMPOSITE=y
+CONFIG_GMAC_TX_DELAY=3
+CONFIG_DEFAULT_DEVICE_TREE="sun7i-a20-bananapi-m1-plus"
+CONFIG_AHCI=y
+# CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
+CONFIG_SPL=y
+CONFIG_SPL_I2C_SUPPORT=y
+# CONFIG_CMD_IMLS is not set
+# CONFIG_CMD_FLASH is not set
+# CONFIG_CMD_FPGA is not set
+# CONFIG_SPL_DOS_PARTITION is not set
+# CONFIG_SPL_ISO_PARTITION is not set
+# CONFIG_SPL_EFI_PARTITION is not set
+CONFIG_NETCONSOLE=y
+CONFIG_ETH_DESIGNWARE=y
+CONFIG_RGMII=y
+CONFIG_SUN7I_GMAC=y
+CONFIG_SCSI=y
+CONFIG_USB_EHCI_HCD=y