elogtool: add next_available_event_offset function

This function is "extracted" from cmd_clear().
This new function will be called from cmd_add(), and new command that
will be added in a future CL (see CL chain).

Additional minor fixes:
 - calls usage() if no valid commands are passed.
 - Slightly improves usage() output. Needed for cmd_clear()

BUG=b:172210863
TEST=elogtool clear

Change-Id: I0d8ecc893675758d7f90845282a588d367b55567
Signed-off-by: Ricardo Quesada <ricardoq@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/57395
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

0 files changed, 0 insertions, 0 deletions