net: qlcnic: add missed unlock in qlcnic_83xx_flash_read32

net: qlcnic: add missed unlock in qlcnic_83xx_flash_read32

qlcnic_83xx_unlock_flash() is called on all paths after we call
qlcnic_83xx_lock_flash(), except for one error path on failure
of QLCRD32(), which may cause a deadlock. This bug is suggested
by a static analysis tool, please advise.

Fixes: 81d0aeb0a4fff ("qlcnic: flash template based firmware reset recovery")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Link: https://lore.kernel.org/r/20210816131405.24024-1-dinghao.liu@zju.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>