ath10k: split ce pipe init/alloc further

Calling init to reinit ce pipe state would also
re-set all static structure links and setting
(which don't change over driver lifecycle).

Make it so alloc links structures and initializes
static data and init part to setup state
variables and clear stuff.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>