Partial revert of xhci: use pm_ptr() instead #ifdef for CONFIG_PM conditionals

Partial revert of xhci: use pm_ptr() instead #ifdef for CONFIG_PM conditionals

commit 9734fd7a2777 ("xhci: use pm_ptr() instead of #ifdef for CONFIG_PM
conditionals") did not quite work properly in the 5.15.y branch where it was
applied to fix a build error when CONFIG_PM was set as it left the following
build errors still present:

	ERROR: modpost: "xhci_suspend" [drivers/usb/host/xhci-pci.ko] undefined!
	ERROR: modpost: "xhci_resume" [drivers/usb/host/xhci-pci.ko] undefined!

Fix this up by properly placing the #ifdef CONFIG_PM in the xhci-pci.c and
hcd.h files to handle this correctly.

Link: https://lore.kernel.org/r/133dbfa0-4a37-4ae0-bb95-1a35f668ec11@w6rz.net
Signed-off-by: Ron Economos <re@w6rz.net>
Link: https://lore.kernel.org/r/d0919169-ee06-4bdd-b2e3-2f776db90971@roeck-us.net
Reported-by: Guenter Roeck <linux@roeck-us.net>
[ Trimmed the partial revert down to an even smaller bit to only be what
  is required to fix the build error - gregkh]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>