msm: ipa: fix for WLAN driver unload failure

Wait for pending packets to be completed before disconnect
should be done only for IPA consumer pipes. This commit
removes the wait logic for IPA producer pipes.

Change-Id: I4d86ac72b6271f46c8b6204cdde7c6913cf183a4
Signed-off-by: Ravi Gummadidala <rgummadi@codeaurora.org>