ice: fix locking in ice_dcb_rebuild()

ice: fix locking in ice_dcb_rebuild()

Move the mutex_lock() call up to prevent that DCB settings change after
the first ice_query_port_ets() call. The second ice_query_port_ets()
call in ice_dcb_rebuild() is already protected by pf->tc_mutex.

This also fixes a bug in an error path, as before taking the first
"goto dcb_error" in the function jumped over mutex_lock() to
mutex_unlock().

This bug has been detected by the clang thread-safety analyzer.

Cc: intel-wired-lan@lists.osuosl.org
Fixes: 242b5e068b25 ("ice: Fix DCB rebuild after reset")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Tested-by: Arpana Arland <arpanax.arland@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260506-jk-iwl-net-2026-05-04-v2-6-a5ea4dc837a9@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>