tc: q_ets: drop dead code from argument parsing

tc: q_ets: drop dead code from argument parsing

Checking for nbands to be at least 1 at this point is useless. Indeed:
- ets requires "bands", "quanta" or "strict" to be specified
- if "bands" is specified, nbands cannot be negative, see parse_nbands()
- if "strict" is specified, nstrict cannot be negative, see
  parse_nbands()
- if "quantum" is specified, nquanta cannot be negative, see
  parse_quantum()
- if "bands" is not specified, nbands is set to nstrict+nquanta
- the previous if statement takes care of the case when none of them are
  specified and nbands is 0, terminating execution.

Thus nbands cannot be < 1 at this point and this code cannot be executed.

Signed-off-by: Andrea Claudi <aclaudi@redhat.com>
Signed-off-by: David Ahern <dsahern@kernel.org>