[media] b2c2: break it into common/pci/usb directories

b2c2 is, in fact, 2 drivers: one for PCI and one for USB, plus
a common bus-independent code. Break it accordingly.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/Kconfig b/drivers/media/Kconfig
index 81c8662..6343e84 100644
--- a/drivers/media/Kconfig
+++ b/drivers/media/Kconfig
@@ -139,7 +139,6 @@
 	  unsure say Y.
 
 comment "Media drivers"
-source "drivers/media/common/Kconfig"
 source "drivers/media/rc/Kconfig"
 
 #
@@ -173,4 +172,7 @@
 	depends on DVB_CORE
 source "drivers/media/dvb-frontends/Kconfig"
 
+# Common drivers
+source "drivers/media/common/Kconfig"
+
 endif # MEDIA_SUPPORT