spi: xilinx_spi: Perform software reset during slave setup

to make sure it is in the clear state.

Signed-off-by: Jason Wu <huanyu@xilinx.com>
diff --git a/drivers/spi/xilinx_spi.h b/drivers/spi/xilinx_spi.h
index 32610d2..69d0b94 100644
--- a/drivers/spi/xilinx_spi.h
+++ b/drivers/spi/xilinx_spi.h
@@ -119,6 +119,9 @@
 #define SPIRFOR_OCYVAL_POS	0
 #define SPIRFOR_OCYVAL_MASK	(0xf << SPIRFOR_OCYVAL_POS)
 
+/* SPI Software Reset Register (ssr) */
+#define SPISSR_RESET_VALUE	0x0a
+
 struct xilinx_spi_slave {
 	struct spi_slave slave;
 	struct xilinx_spi_reg *regs;