USB: gadget: f_qdss: do bam disconnect during qdss channel close

Currently qdss driver is not doing bam pipe disconnect when qdss
channel is closed. This results in not doing bam pipe reset during
next bam connect which could cause USB BAM accessing invalid address
and results in crash. Hence do bam disconnect during qdss channel
close so that when bam pipe reset happens during bam connect as part
of qdss channel close.

CRs-Fixed: 656956
Change-Id: Iba2e012894155e664121907139c0c35e72080818
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>