pci(4): unbreak the build

`argsp` is not defined in `generic_pcie_unmap_resource(..)`. Remove the
parameter passed to `bus_generic_unmap_resource(..)` as this parameter
is never passed to `generic_pcie_unmap_resource(..)`.

Fixes:	9805612 ("acpi/pci/vmd: Fix a nit with nested resource mapping requests")
Reported by:	Jenkins (aarch64, armv6, armv7, etc)
Differential Revision:	https://reviews.freebsd.org/D45493

sys/dev/pci/pci_host_generic.c

@@ -666,7 +666,7 @@ generic_pcie_unmap_resource(device_t dev, device_t child, struct resource *r,
 	case SYS_RES_MEMORY:
 		break;
 	default:
-		return (bus_generic_unmap_resource(dev, child, r, argsp, map));
+		return (bus_generic_unmap_resource(dev, child, r, map));
 	}
 
 	range = generic_pcie_containing_range(dev, type, rman_get_start(r),