Passing padding information to the driver -- hal.

This CL changes the sAIDL interface to enable passing padding
information of the shared memory pool to the driver.

The sAIDL interface defines the padding field explicitly in DataLocation
to make it easy to convert to/from the canonical request.

Bug: 179691454
Test: NNT_static
Test: VtsHalNeuralnetworksTargetTest
Change-Id: Ie13b421531ee4df48822086b027d94a622a3518c
Merged-In: Ie13b421531ee4df48822086b027d94a622a3518c
(cherry picked from commit 6365ea1d)