ath10k: remove the repeated declaration

Functions 'ath10k_pci_free_pipes' and 'ath10k_wmi_alloc_skb'
are declared twice in their header file, so remove the repeated
declaration.

Cc: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1622448459-50805-1-git-send-email-zhangshaokun@hisilicon.com