stm32/mboot/gzstream: Fix lost data decompressing final part of file.
stm32/mboot/gzstream: Fix lost data decompressing final part of file.

Prior to this fix, the final piece of data in a compressed file may have
been lost when decompressing.

Signed-off-by: Damien George <99e6b749acbfbe2a596df99e91d24d6e1fdbee00@micropython.org>

bvernoux/micropython,henriknelson/micropython,bvernoux/micropython,bvernoux/micropython,adafruit/circuitpython,adafruit/circuitpython,henriknelson/micropython,henriknelson/micropython,bvernoux/micropython,adafruit/circuitpython,adafruit/circuitpython,henriknelson/micropython,bvernoux/micropython,adafruit/circuitpython,adafruit/circuitpython,henriknelson/micropython