memory: brcmstb_dpfe: Fix memory leak

memory: brcmstb_dpfe: Fix memory leak

In brcmstb_dpfe_download_firmware(), memory is allocated to variable fw by
firmware_request_nowarn(), but never released. Fix up to release fw on
all return paths.

Cc: <stable@vger.kernel.org>
Fixes: 2f330caff577 ("memory: brcmstb: Add driver for DPFE")
Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
Acked-by: Markus Mayer <mmayer@broadcom.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20200820172118.781324-1-alex.dewar90@gmail.com
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>