simpleperf: inject cmd: accept missing aux data

Some ETM data can be dropped when recording if the userspace buffer
is full. The inject cmd shouldn't treat this as an error.

Also add a suggestion to increase userspace buffer size if some ETM
data is dropped when recording.

Bug: none
Test: run simpleperf_unit_test
Change-Id: I7da115b30c1c5f0711883284b0a5bb982f2bdd6d
7 files changed