doc: update bcmfs guide
doc: update bcmfs guide

Update bcmfs.rst file with supported features and devices.

Signed-off-by: Vikas Gupta <7ae8af690dee9c76d75bc62cad6c6ddd79ca1b46@broadcom.com>
Reviewed-by: Ajit Khaparde <01965fbd61169dc18f3fb5e13de7f67d298f8924@broadcom.com>
Reviewed-by: JP Lee <ee276056aac3306a0a0e27041764ed183bc61a47@broadcom.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk