PCI: hv: Add check for hyperv_initialized in init_hv_pci_drv()

Add check for hv_is_hyperv_initialized() at the top of
init_hv_pci_drv(), so if the pci-hyperv driver is force-loaded on non
Hyper-V platforms, the init_hv_pci_drv() will exit immediately, without
any side effects, like assignments to hvpci_block_ops, etc.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reported-and-tested-by: Mohammad Alqayeem <mohammad.alqyeem@nutanix.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/1621984653-1210-1-git-send-email-haiyangz@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

Author: haiyangz

drivers/pci/controller/pci-hyperv.c

@@ -3476,6 +3476,9 @@ static void __exit exit_hv_pci_drv(void)
 
 static int __init init_hv_pci_drv(void)
 {
+	if (!hv_is_hyperv_initialized())
+		return -ENODEV;
+
 	/* Set the invalid domain number's bit, so it will not be used */
 	set_bit(HVPCI_DOM_INVALID, hvpci_dom_map);