be2net: Free/delete pmacs (in be_clear()) only if they exist

During suspend-resume and lancer error recovery we will cleanup and
re-initialize the resources through be_clear() and be_setup() respectively.
During re-initialisation in be_setup(), if be_get_config() fails, we'll again
call be_clear() which will cause a NULL pointer dereference as adapter->pmac_id is
already freed.

Signed-off-by: Kalesh AP <kalesh.purayil@emulex.com>
Signed-off-by: Somnath Kotur <somnath.kotur@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>