Bluetooth: Fix endianness handling of cmd_status/complete opcodes

The opcode in cmd_complete and cmd_status events is 16 bits, so we
should only be comparing it after having converted it to the host
endianness. There's already an opcode variable in both functions which
is in host endiannes so the right fix is to just start using it instead
of ev->opcode.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>