usb: bam: Update pipe_enabled_per_bam

Without this fix, pipe_enabled_per_bam is not updated
correctly when disconnecting IPA. This result in
USB Consumer resource stuck on EINPROGRESS.

Change-Id: I4262bf54a5cb7cfcabcf31083b9c8200ea0469a0
Signed-off-by: Bar Weiner <bweiner@codeaurora.org>