radio-tavarua: Modified the device count handling mechanism

Replaced the existing mutex lock with atomic increment/decrement
operations for manipulating the device count.

Change-Id: Ic08b3861f06620acbc68b6ca0aea7c622e7027b3
CRs-Fixed: 296214
Signed-off-by: Anantha Krishnan <ananthk@codeaurora.org>
1 file changed