ath10k: Wait for peer delete response to synchronize with fw

Peer creation in firmware fails if last peer deletion is still
in progress.
Wait for peer delete response from firmware after deleting peer
from host driver.

CRs-Fixed: 2047126
Change-Id: I9eb01393d9cd3dd82f2084262c250081f2076b46
Signed-off-by: Ashutosh Kumar <askuma@codeaurora.org>