simpleperf: read kernel module build id from file.

Profcollectd doesn't have permission to read kernel module build id from
sysfs. So support reading kernel module build id from file.

Bug: 183135316
Test: run simpleperf_unit_test.
Test: run simpleperf manually.
Change-Id: Iac3b05df4ba07d8ec84cafb39799f282ba15ff4d
1 file changed