forcedeth: Fix an error handling path in nv_probe()

forcedeth: Fix an error handling path in nv_probe()

If an error occures after calling nv_mgmt_acquire_sema(), it should be
undone with a corresponding nv_mgmt_release_sema() call.

Add it in the error handling path of the probe as already done in the
remove function.

Fixes: cac1c52c3621 ("forcedeth: mgmt unit interface")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Zhu Yanjun <zyjzyj2000@gmail.com>
Link: https://lore.kernel.org/r/355e9a7d351b32ad897251b6f81b5886fcdc6766.1684571393.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Jakub Kicinski <kuba@kernel.org>