Remove duplicate parser for ENTER_BMPS_RSP
Reuse common rsp parse block for DELETE_BSS_RSP

Some commands have same response structure. Reuse the
parser block also for DELTE_BSS_RSP parsing to avoid
code duplication.
Rename protofield bss_index to bssIdx.
Use a common bssIdx protofield for all requests.
Use a common bssId protofield for all commands
Reuse the bssIdx protofield also for responses
Remove empty line