msm: adsprpc: use current PID instead of stored PID for validation

Use PID from task struct instead of PID stored during get info to
validate whether the calling process is a trusted application, so
that the sessions feature where the PID is tweaked for the second
session does not return a false failure.

Change-Id: I177283ccf2333b762148398e299e64d76dbc1926
Acked-by: Thyagarajan Venkatanarayanan <venkatan@qti.qualcomm.com>
Signed-off-by: Himateja Reddy <hmreddy@codeaurora.org>