ath10k: move ath10k_hw_params definition to hw.h

This is to prepare for rx descriptor abstraction where we'll
be dereferencing ath10k_hw_params member in hw.h. Moreover
hw.h looks more suitable to house ath10k_hw_params definition
than core.h

Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>