spi: Add HTC spi_write_and_read function in spi.c

Change-Id: Ia7ca04d6bff5f5ab11045cf7e78153925b815191
Signed-off-by: Flemmard <flemmard@gmail.com>
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index fa702ae..b6a6f6c 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -685,6 +685,9 @@
 		const void *txbuf, unsigned n_tx,
 		void *rxbuf, unsigned n_rx);
 
+extern int spi_write_and_read(struct spi_device *spi,
+		u8 *txbuf, u8 *rxbuf, unsigned size);
+
 /**
  * spi_w8r8 - SPI synchronous 8 bit write followed by 8 bit read
  * @spi: device with which data will be exchanged