stlink: add packages

stlink: add packages

stlink is an open source toolset to program and debug STM32 devices
and boards manufactured by STMicroelectronics.

Resulting binary packages:
 * stlink - library and shared chip info data
 * st-info - a programmer and chip information tool
 * st-flash - a flash manipulation tool
 * st-trace - a logging tool to record information on execution
 * st-util - a GDB server

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
(cherry picked from commit e609f6acdf3e4619d691d5325efb9cc8a9a1b9fa)