CMD_GET_STATUS is not supported by some devices implementing
RDU2-compatible ICD as well as "legacy" devices. To account for that
fact, add code that obtains the same information (app/bootloader FW
version) using several different commands.

This is a backport of Linux kernel patch [1]

[1] https://lore.kernel.org/lkml/20180707024108.32373-5-andrew.smirnov@gmail.com/T/#md1b7130a992235d57cabadc8e59fc74ee3b21d9e

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>