ath10k: fix build errors with !CONFIG_PM

ath10k: fix build errors with !CONFIG_PM

Build errors have been reported with CONFIG_PM=n:

drivers/net/wireless/ath/ath10k/pci.c:3416:8: error: implicit
declaration of function 'ath10k_pci_suspend'
[-Werror=implicit-function-declaration]

drivers/net/wireless/ath/ath10k/pci.c:3428:8: error: implicit
declaration of function 'ath10k_pci_resume'
[-Werror=implicit-function-declaration]

These are caused by the combination of the following two commits:

6af1de2e4ec4 ("ath10k: mark PM functions as __maybe_unused")
96378bd2c6cd ("ath10k: fix core PCI suspend when WoWLAN is supported but
disabled")

Both build fine on their own.

But now that ath10k_pci_pm_{suspend,resume}() is compiled
unconditionally, we should also compile ath10k_pci_{suspend,resume}()
unconditionally.

And drop the #ifdef around ath10k_pci_hif_{suspend,resume}() too; they
are trivial (empty), so we're not saving much space by compiling them
out. And the alternatives would be to sprinkle more __maybe_unused, or
spread the #ifdef's further.

Build tested with the following combinations:
CONFIG_PM=y && CONFIG_PM_SLEEP=y
CONFIG_PM=y && CONFIG_PM_SLEEP=n
CONFIG_PM=n

Fixes: 96378bd2c6cd ("ath10k: fix core PCI suspend when WoWLAN is supported but disabled")
Fixes: 096ad2a15fd8 ("Merge branch 'ath-next'")
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>