ACPI/PCI: Remove useless NULL pointer checks

Local variable 'p' is initialized by an address of field of acpi_resource,
so it does not make sense to compare 'p' with NULL.

Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: Andrey Strachuk <strochuk@ispras.ru>
Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/pci_link.c

@@ -95,7 +95,7 @@ static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
 	case ACPI_RESOURCE_TYPE_IRQ:
 		{
 			struct acpi_resource_irq *p = &resource->data.irq;
-			if (!p || !p->interrupt_count) {
+			if (!p->interrupt_count) {
 				acpi_handle_debug(handle,
 						  "Blank _PRS IRQ resource\n");
 				return AE_OK;
@@ -121,7 +121,7 @@ static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
 		{
 			struct acpi_resource_extended_irq *p =
 			    &resource->data.extended_irq;
-			if (!p || !p->interrupt_count) {
+			if (!p->interrupt_count) {
 				acpi_handle_debug(handle,
 						  "Blank _PRS EXT IRQ resource\n");
 				return AE_OK;
@@ -182,7 +182,7 @@ static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
 	case ACPI_RESOURCE_TYPE_IRQ:
 		{
 			struct acpi_resource_irq *p = &resource->data.irq;
-			if (!p || !p->interrupt_count) {
+			if (!p->interrupt_count) {
 				/*
 				 * IRQ descriptors may have no IRQ# bits set,
 				 * particularly those w/ _STA disabled
@@ -197,7 +197,7 @@ static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
 		{
 			struct acpi_resource_extended_irq *p =
 			    &resource->data.extended_irq;
-			if (!p || !p->interrupt_count) {
+			if (!p->interrupt_count) {
 				/*
 				 * extended IRQ descriptors must
 				 * return at least 1 IRQ