ALSA: move line6 usb driver into sound/usb

Promote line6 driver from staging to sound/usb/line6 directory, and
maintain through sound subsystem tree.

This commit just moves the code and adapts Makefile / Kconfig.
The further renames and misc cleanups will follow.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --cc drivers/staging/Kconfig
Simple merge

diff --cc drivers/staging/Makefile
Simple merge

diff --cc sound/usb/Kconfig
Simple merge

diff --cc sound/usb/Makefile
Simple merge

diff --cc sound/usb/line6/Kconfig
Simple merge

diff --cc sound/usb/line6/Makefile
Simple merge

diff --cc sound/usb/line6/audio.c
Simple merge

diff --cc sound/usb/line6/audio.h
Simple merge

diff --cc sound/usb/line6/capture.c
Simple merge

diff --cc sound/usb/line6/capture.h
Simple merge

diff --cc sound/usb/line6/driver.c
Simple merge

diff --cc sound/usb/line6/driver.h
Simple merge

diff --cc sound/usb/line6/midi.c
Simple merge

diff --cc sound/usb/line6/midi.h
Simple merge

diff --cc sound/usb/line6/midibuf.c
Simple merge

diff --cc sound/usb/line6/midibuf.h
Simple merge

diff --cc sound/usb/line6/pcm.c
Simple merge

diff --cc sound/usb/line6/pcm.h
Simple merge

diff --cc sound/usb/line6/playback.c
Simple merge

diff --cc sound/usb/line6/playback.h
Simple merge

diff --cc sound/usb/line6/pod.c
Simple merge

diff --cc sound/usb/line6/pod.h
Simple merge

diff --cc sound/usb/line6/podhd.c
Simple merge

diff --cc sound/usb/line6/podhd.h
Simple merge

diff --cc sound/usb/line6/revision.h
Simple merge

diff --cc sound/usb/line6/toneport.c
Simple merge

diff --cc sound/usb/line6/toneport.h
Simple merge

diff --cc sound/usb/line6/usbdefs.h
Simple merge

diff --cc sound/usb/line6/variax.c
Simple merge

diff --cc sound/usb/line6/variax.h
Simple merge