CRAS: hfp_info - Consolidate temp buffer and packet size check

Rename hci_sco_buf to read_buf so it's more readable.
Replace use of HCI_SCO_PKT_SIZE by info->packet_size, since
this value could be different per platform.
Add supported packet size and the corresponding temp buffer
size to use explicitly, and change temp buffer allocation
to a dynamical way.  Also added code to assert packet_size
doesn't exceed read buffer size.

BUG=b:162802621
TEST=Verify WBS on Atlas

Change-Id: I82444726ff44b2ab85f97d53c0d7aad140c77014
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/adhd/+/2421388
Reviewed-by: En-Shuo Hsu <enshuo@chromium.org>
Tested-by: Hsinyu Chao <hychao@chromium.org>
Commit-Queue: Hsinyu Chao <hychao@chromium.org>
2 files changed