ethtool: module: avoid leaking a netdev ref on module flash errors

ethtool: module: avoid leaking a netdev ref on module flash errors

module_flash_fw_schedule() is missing undo for setting
the "in_progress" flag and taking the netdev reference.
Delay taking these, the device can't disappear while
we are holding rtnl_lock.

Fixes: 32b4c8b53ee7 ("ethtool: Add ability to flash transceiver modules' firmware")
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Link: https://patch.msgid.link/20260522231312.1710836-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>