radio: iris: Fix the issue with multiple enable cmds

Driver sending enable cmds to controller even it is already in ON.
Send error response to enable cmd,if the controller is already ON.

CRs-Fixed: 818067
Change-Id: I4a5ad70bfe782a29dc66a42c4cad7ec6e9ecf85c
Signed-off-by: Venkateshwarlu Domakonda <vdomak@codeaurora.org>