diag: Prevent switching mode for non mdlog process

Switching the mode between USB and PCIE is incorrectly happening
while closing non mdlog process. Patch prevents this issue case
for non mdlog process by checking against the pid of the process
which caused the switch between USB and PCIE.

Change-Id: I609076633fe9dd20287cfc35f0098004bdd11618
Signed-off-by: Manoj Prabhu B <bmanoj@codeaurora.org>