p2p: Flush the p2p scan result on group remove event

Flush out p2p scan results on receiving group removal event.
p2p scan window will be updated on next p2p scan.

Change-Id: I3bcfed355574478bda2cac688b7df956c2701683
CRs-Fixed: 504022
(cherry picked from commit eaeecac20b125ffff8fea7a12b514999fff6bf5f)
(cherry picked from commit 3541e2cb0768865ecc312ead33f48c673e177ac3)