spi: rcar: add Renesas QSPI support on RSPI

The R8A7790 has QSPI module which is very similar to RSPI.
This patch adds into RSPI module together to supports QSPI module.

Signed-off-by: Hiep Cao Minh <cm-hiep@jinso.co.jp>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/include/linux/spi/rspi.h b/include/linux/spi/rspi.h
index 900f0e3..a25bd6f 100644
--- a/include/linux/spi/rspi.h
+++ b/include/linux/spi/rspi.h
@@ -26,6 +26,8 @@
 	unsigned int dma_rx_id;
 
 	unsigned dma_width_16bit:1;	/* DMAC read/write width = 16-bit */
+
+	u16 num_chipselect;
 };
 
 #endif