In case memory resources for fw were succesfully allocated, release
them before jumping to fw_load_fail.

Addresses-Coverity-ID: 1466092 ("Resource leak")
Fixes: c3b2f7ca ("qtnfmac: implement asynchronous firmware loading")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>