USB: <linux/usb_ch9.h> becomes <linux/usb/ch9.h>

This moves <linux/usb_ch9.h> to <linux/usb/ch9.h> to reduce some of the
clutter of usb header files.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/linux/usb/Kbuild b/include/linux/usb/Kbuild
new file mode 100644
index 0000000..43f160c
--- /dev/null
+++ b/include/linux/usb/Kbuild
@@ -0,0 +1,5 @@
+unifdef-y += audio.h
+unifdef-y += cdc.h
+unifdef-y += ch9.h
+unifdef-y += midi.h
+