USB: dwc3-msm: Perform DBM config/unconfig under spinlock protection

There is a possibility of dwc3_msm_ep_queue() and msm_ep_unconfig() racing
each other if suspend happens right after configured. This scenario will
result in NOC error if start_xfer command gets queued after
msm_ep_unconfig().  Hence fix the issue by adding spinlock protection for
DBM endpoint configuration and unconfiguration.

Change-Id: I3fd007647370250017c97faebffadb35afb7fc4d
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>
Signed-off-by: Chandana Kishori Chiluveru <cchiluve@codeaurora.org>
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>