ice: fix eswitch code memory leak in reset scenario

Add simple eswitch mode checker in attaching VF procedure and allocate
required port representor memory structures only in switchdev mode.
The reset flows triggers VF (if present) detach/attach procedure.
It might involve VF port representor(s) re-creation if the device is
configured is switchdev mode (not legacy one).
The memory was blindly allocated in current implementation,
regardless of the mode and not freed if in legacy mode.

Kmemeleak trace:
unreferenced object (percpu) 0x7e3bce5b888458 (size 40):
  comm "bash", pid 1784, jiffies 4295743894
  hex dump (first 32 bytes on cpu 45):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc 0):
    pcpu_alloc_noprof+0x4c4/0x7c0
    ice_repr_create+0x66/0x130 [ice]
    ice_repr_create_vf+0x22/0x70 [ice]
    ice_eswitch_attach_vf+0x1b/0xa0 [ice]
    ice_reset_all_vfs+0x1dd/0x2f0 [ice]
    ice_pci_err_resume+0x3b/0xb0 [ice]
    pci_reset_function+0x8f/0x120
    reset_store+0x56/0xa0
    kernfs_fop_write_iter+0x120/0x1b0
    vfs_write+0x31c/0x430
    ksys_write+0x61/0xd0
    do_syscall_64+0x5b/0x180
    entry_SYSCALL_64_after_hwframe+0x76/0x7e

Testing hints (ethX is PF netdev):
- create at least one VF
    echo 1 > /sys/class/net/ethX/device/sriov_numvfs
- trigger the reset
    echo 1 > /sys/class/net/ethX/device/reset

Fixes: 415db839 ("ice: make representor code generic")
Signed-off-by: Grzegorz Nitka <grzegorz.nitka@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Tested-by: Rinitha S <sx.rinitha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>