simpleperf: Suppress kernel module read warnings

Kernel modules may come from vendor_kernel_ramdisk.img, which isn't
accessed from userspace. Kernel module symbols are also available in
/proc/kallsyms, making read-failure warnings unnecessary.

So suppress warnings when kernel modules can't be read.
Also update kernel module search locations in environment.cpp for
consistency.

Bug: none
Test: run simpleperf_unit_test
Test: run simpleperf manually
Change-Id: I1345cc02582617a24e31908d8b67da884932b24e
3 files changed