dt-bindings: net: bluetooth: Minor fix in broadcom-bluetooth

The example for brcm,bt-pcm-int-params should be a bytestring and all
values need to be two hex characters.

Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>