ath10k: clean up growing hw checks during safe and full reset

Store pci chip secific reset funtions in struct ath10k_pci
as callbacks during early ath10k_pci_probe() and use the
callback to perform chip specific resets. This patch essentially
adds two callback in ath10k_pci, one for doing soft reset and
the other for hard reset. By using callbacks we can get rid of
those hw revision checks in ath10k_pci_safe_chip_reset() and
ath10k_pci_chip_reset(). As such this patch does not fix
any issue.

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