Bluetooth: Controller: Skip re-init of static initialized PDU fields

Skip re-initialization of statically initialized PDU struct
fields that are not modified at runtime.

When supporting connection oriented CTE, the cp bit and
resv field used for CTE info are modified, hence
re-initialized these and accordingly reset the values
when just-in-time HCI Tx Data fragmentation is performed
in the Lower Link Layer.

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>