bus/fslmc: fix resource leak

bus/fslmc: fix resource leak

1 issue caught by coverity (issue 344967).
Leaked_storage: Variable sep going out of scope leaks the
storage it points to.

When 'sep' is not null and sep_exist is 0, 'sep' is freed
before going out of scope of the function irrespective of
'addr' exists or not.

Coverity issue: 344967
Fixes: e67a61614d0b ("bus/fslmc: support device iteration")
Cc: stable@dpdk.org
Signed-off-by: Agalya Babu RadhaKrishnan <agalyax.babu.radhakrishnan@intel.com>
Acked-by: Sachin Saxena <sachin.saxena@nxp.com>