ice: do not setup vlan for loopback VSI

stable inclusion
from stable-v5.10.135
commit 160f79561e8746d69023a1cad6c80ebaf6be81f7
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5ZWFM

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=160f79561e8746d69023a1cad6c80ebaf6be81f7



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commit cc019545 upstream.

Currently loopback test is failiing due to the error returned from
ice_vsi_vlan_setup(). Skip calling it when preparing loopback VSI.

Fixes: 0e674aeb ("ice: Add handler for ethtool selftest")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: George Kuruvinakunnel <george.kuruvinakunnel@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>