V4L/DVB (12413): radio-si470x: separate common and usb code

This patch is a preceding work to add the i2c interface of si470x.
The si470x directory includes a common file and usb specific file and
header file.
The part unrelated with usb interface and i2c interface exists in
radio-si470x-common.c file, and The usb specific part exists in
radio-si470x-usb.c file.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
[tobias.lorenz@gmx.net: Small changes, due to new include "linux/smp_lock.h"]
Signed-off-by: Tobias Lorenz <tobias.lorenz@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/radio/Kconfig

@@ -351,29 +351,11 @@ config USB_DSBR
 	  To compile this driver as a module, choose M here: the
 	  module will be called dsbr100.
 
-config USB_SI470X
-	tristate "Silicon Labs Si470x FM Radio Receiver support"
-	depends on USB && VIDEO_V4L2
-	---help---
-	  This is a driver for USB devices with the Silicon Labs SI470x
-	  chip. Currently these devices are known to work:
-	  - 10c4:818a: Silicon Labs USB FM Radio Reference Design
-	  - 06e1:a155: ADS/Tech FM Radio Receiver (formerly Instant FM Music)
-	  - 1b80:d700: KWorld USB FM Radio SnapMusic Mobile 700 (FM700)
-
-	  Sound is provided by the ALSA USB Audio/MIDI driver. Therefore
-	  if you don't want to use the device solely for RDS receiving,
-	  it is recommended to also select SND_USB_AUDIO.
-
-	  Please have a look at the documentation, especially on how
-	  to redirect the audio stream from the radio to your sound device:
-	  Documentation/video4linux/si470x.txt
-
-	  Say Y here if you want to connect this type of radio to your
-	  computer's USB port.
+config RADIO_SI470X
+	bool "Silicon Labs Si470x FM Radio Receiver support"
+	depends on VIDEO_V4L2
 
-	  To compile this driver as a module, choose M here: the
-	  module will be called radio-si470x.
+source "drivers/media/radio/si470x/Kconfig"
 
 config USB_MR800
 	tristate "AverMedia MR 800 USB FM radio support"

drivers/media/radio/Makefile

@@ -17,7 +17,7 @@ obj-$(CONFIG_RADIO_GEMTEK_PCI) += radio-gemtek-pci.o
 obj-$(CONFIG_RADIO_TRUST) += radio-trust.o
 obj-$(CONFIG_RADIO_MAESTRO) += radio-maestro.o
 obj-$(CONFIG_USB_DSBR) += dsbr100.o
-obj-$(CONFIG_USB_SI470X) += radio-si470x.o
+obj-$(CONFIG_RADIO_SI470X) += si470x/
 obj-$(CONFIG_USB_MR800) += radio-mr800.o
 obj-$(CONFIG_RADIO_TEA5764) += radio-tea5764.o