usbdev: Extract libusb1 device discovery into a separate file

Currently there is a TODO-like comment in the dediprog driver: "Might be
useful for other USB devices as well". Act on this comment by collecting
all the device discovery code for libusb1 devices into a separate file.

Change-Id: Idfcc79371241c2c1dea97faf5e532aa971546a79
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-on: https://review.coreboot.org/27443
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/Makefile b/Makefile
index ddfd711..b13cf7e 100644
--- a/Makefile
+++ b/Makefile
@@ -1023,6 +1023,7 @@
 ifneq ($(NEED_LIBUSB1), )
 CHECK_LIBUSB1 = yes
 FEATURE_CFLAGS += -D'NEED_LIBUSB1=1'
+PROGRAMMER_OBJS += usbdev.o
 # FreeBSD and DragonflyBSD use a reimplementation of libusb-1.0 that is simply called libusb
 ifeq ($(TARGET_OS),$(filter $(TARGET_OS),FreeBSD DragonFlyBSD))
 USB1LIBS += -lusb