The problem was that one needs to STATICALLY allocate the buffer
that sends the data to the GPS. In this case, making the rxbuf
static inside gps/main.c fixed the problem.

For safety, the buffer inside usbdbg_puts() was also made static, and aligned
to a word (32-bit) boundary, as advised by the SiLabs USB device library.

usbled host-side s/w controls blinking the LEDs
EFM32 code in usbdcdc

Conflicts:
	sw/os-comparison/freertos_blink/armgcc/Makefile

Signed-off-by: Theodor Stana <t.stana@cern.ch>