arm: sunxi: Allwinner A10 SPI driver

Add spi driver for sun4i, sun5i and sun7i SoCs. The driver is
adapted from mailine kernel.

Signed-off-by: Stefan Mavrodiev <stefan@olimex.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 95b03a2..728e30c 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -44,6 +44,7 @@
 obj-$(CONFIG_SH_SPI) += sh_spi.o
 obj-$(CONFIG_SH_QSPI) += sh_qspi.o
 obj-$(CONFIG_STM32_QSPI) += stm32_qspi.o
+obj-$(CONFIG_SUN4I_SPI) += sun4i_spi.o
 obj-$(CONFIG_TEGRA114_SPI) += tegra114_spi.o
 obj-$(CONFIG_TEGRA20_SFLASH) += tegra20_sflash.o
 obj-$(CONFIG_TEGRA20_SLINK) += tegra20_slink.o