lmkd: Fix killed process name reporting

Fix termination of killed process name in proc_get_name function. While at
it also fix the coding style in the function.

Test: lmkd_unit_test
Bug: 141780598
Change-Id: I3f99b3e37b9a9d0750ece94f08f0b50ac839dacb
Signed-off-by: Suren Baghdasaryan <surenb@google.com>