Revert "net: wwan: iosm: Keep device at D0 for s2idle case"

Depending on BIOS configuration IOSM driver exchanges
protocol required for putting device into D3L2 or D3L1.2.

ipc_pcie_suspend_s2idle() is implemented to put device to D3L1.2.

This patch forces PCI core know this device should stay at D0.
- pci_save_state()is expensive since it does a lot of slow PCI
config reads.

The reported issue is not observed on x86 platform. The supurios
wake on AMD platform needs to be futher debugged with orignal patch
submitter [1]. Also the impact of adding pci_save_state() needs to be
assessed by testing it on other platforms.

This reverts commit f4dd5174("net: wwan: iosm: Keep device
at D0 for s2idle case").

[1] https://lore.kernel.org/all/20211224081914.345292-2-kai.heng.feng@canonical.com/Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Link: https://lore.kernel.org/r/20220104150213.1894-1-m.chetan.kumar@linux.intel.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/wwan/iosm/iosm_ipc_pcie.c

@@ -340,9 +340,6 @@ static int __maybe_unused ipc_pcie_suspend_s2idle(struct iosm_pcie *ipc_pcie)
 
 	ipc_imem_pm_s2idle_sleep(ipc_pcie->imem, true);
 
-	/* Let PCI core know this device should stay at D0 */
-	pci_save_state(ipc_pcie->pci);
-
 	return 0;
 }