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>
a2bf94d4c1