wlan: use spin_lock and spin_unlock for smd response data

spin_lock and spin_unlock to synchronise smd response data
instead of spin_lock_bh and spin_unlock_bh as these are not
triggered in user context.

Change-Id: If9fa415e2675d7c25a91b8f92b5e5a400e8a3051
CRs-Fixed: 2733663