qcacld-3.0: Fix uninitialized sessionId usage on error

The return value from csr_roam_get_session_id_from_bssid() isn't
checked, and when it returns an error, it won't initialize sessionId.
Fix it by checking the return value, and exiting when there's an error.

Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: Forenche <prahul2003@gmail.com>
Signed-off-by: improbir <ghosh_probir@yahoo.com>