Stellaris: Add initial USB support up to enumeration

This allows the Stellaris to enumerate as a VultureProg device.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Include QiProg as a submodule

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Make USB control callback respond to VENDOR requests

The USB control callback was erroneously responding to CLASS requests,
instead of VENDOR requests. As a result, QiProg control messages were not
reaching out callback.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Stellaris: Hook QiProg device code in the build

QiProg contains a very this layer which translates USB commands into
QiProg calls. Include these files, and the QiProg core into the build.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Stellaris: Add skeleton for lpc driver, and hook it to QiProg

Add a skeleton for an LPC driver, and use the QiProg USB device translator
to call the driver on USB control requests. With this commit, it becomes
possible to query the Stellaris with qiprog_get_capabilities().

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Stellaris: Fix "unused parameter" warnings in qiprog_lpc.c

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Update qiprog submodule

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
usb_dev.c: Print the bRequestValue instead of bmRequestType

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Stellaris: Add stub for set_bus in LPC driver

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Stellaris: Add stub for read_chip_id in LPC driver

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Stellaris: Add stubs for read/write[8/16/32]

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>