the USB trace now respects the global setting.
the verbosity is also decreased, not showing USB activity unless
debugging.
this also saves some space.
the reset cause is now printed.
the strings increase the bootloader size, but it already exceeded
the 16 kB limit when trace level is set to info.
Change-Id: I9ba08d4bb4f188f6e7a202ea86acb7a42a2054f3
We need to refer to g_dfu as a pointer from all code. In DFU mode, it
gets assigned to the address of _g_dfu, which is placed by the linker
script at the start of RAM. In runtime mode, the pointer is statically
defined to point at the start of RAM. The linker script for the runtime
(dfu environment) is adjusted to save the first 32 bytes for the _g_dfu
structure.
This way we can easily check with 'diff' for differences in our code and
Atmel softpack. Also, this layout is more suitable for building various
different firmware images (e.g. factory-test, dfu-loader, main
application) for a variety of different boards (simtrace, owhw, qmod).
