msm: mdm: Set flag to not power down QSC after dump collection.

In the case of SGLTE, the power down function for the external modem
will not get called after its ramdump collection is done.

Change-Id: Id71a549b775d83a7e09cd9daab913def09c1ef84
Signed-off-by: Ameya Thakur <ameyat@codeaurora.org>