Created new directories to hold SPI-related files

drivers/Kconfig

@@ -150,33 +150,10 @@ menuconfig SPI
 	---help---
 		This selection enables selection of common SPI options.  This option
 		should be enabled by all platforms that support SPI interfaces.
-		See include/nuttx/spi.h for further SPI driver information.
+		See include/nuttx/spi/spi.h for further SPI driver information.
 
 if SPI
-config SPI_OWNBUS
-	bool "SPI single device"
-	default n
-	---help---
-		Set if there is only one active device on the SPI bus.  No locking or
-		SPI configuration will be performed. It is not necessary for clients to
-		lock, re-configure, etc..
-
-config SPI_EXCHANGE
-	bool "SPI exchange"
-	default y
-	---help---
-		Driver supports a single exchange method (vs a recvblock() and
-		sndblock() methods).
-
-config SPI_CMDDATA
-	bool "SPI CMD/DATA"
-	default n
-	---help---
-		Devices on the SPI bus require out-of-band support to distinguish
-		command transfers from data transfers.  Such devices will often support
-		either 9-bit SPI (yech) or 8-bit SPI and a GPIO output that selects
-		between command and data.
-
+source drivers/spi/Kconfig
 endif
 
 menuconfig RTC