bluetooth: host: a2dp:error_code should be detailed in set_config_rsp

Error codes fall into two main categories:
case 1: NOT_SUPPORT_XXX. This means that the configuration of the
parameter is not supported locally.
case 2: INVALID_XXX. This means that the parameter is not configured or
duplicated in the set_config_req command.

Currently the protocol only supports SBC, so it is only checked for SBC
parameters.

Signed-off-by: Cheng Chang <cheng.chang@nxp.com>