Document the default alignment and padding value.

This CL documents the default value of the preferred alignment and
padding for request memories.

Bug: 179799921
Test: m
Change-Id: I89c16c3e20939a0ad68d9e3b0061c4a16dc00d8b
Merged-In: I89c16c3e20939a0ad68d9e3b0061c4a16dc00d8b
(cherry picked from commit e6dcc9a38d3fbc2cbd957577657493e36783d3ed)
1 file changed