ath10k: Remove ath10k_qmi_register_service_notifier() declaration

The ath10k/qmi.h header file contains a declaration for the function
ath10k_qmi_register_service_notifier().  This function doesn't exist.
Remove the declaration.

This patch is a no-op and was just found by code inspection.

Fixes: ba94c753cc ("ath10k: add QMI message handshake for wcn3990 client")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200528122105.1.I31937dce728b441fd72cbe23447bc4710fd56ddb@changeid

drivers/net/wireless/ath/ath10k/qmi.h

@@ -115,7 +115,6 @@ int ath10k_qmi_wlan_enable(struct ath10k *ar,
 			   enum wlfw_driver_mode_enum_v01 mode,
 			   const char *version);
 int ath10k_qmi_wlan_disable(struct ath10k *ar);
-int ath10k_qmi_register_service_notifier(struct notifier_block *nb);
 int ath10k_qmi_init(struct ath10k *ar, u32 msa_size);
 int ath10k_qmi_deinit(struct ath10k *ar);
 int ath10k_qmi_set_fw_log_mode(struct ath10k *ar, u8 fw_log_mode);