ACPI: pci_root: Unify the message printing

In acpi_pci_root_add(), pr_info() is added with PREFIX, but
in acpi_pci_root_remap_iospace() the pr_info() with no
PREFIX.

Introduce pr_fmt() to unify the message printing and remove
the PREFIX.

Signed-off-by: Hanjun Guo <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/acpi/pci_root.c

···
  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <[e-mail]>
  */
 
+#define pr_fmt(fmt) "ACPI: " fmt
+
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
···
 		goto end;
 	}
 
-	pr_info(PREFIX "%s [%s] (domain %04x %pR)\n",
+	pr_info("%s [%s] (domain %04x %pR)\n",
 	       acpi_device_name(device), acpi_device_bid(device),
 	       root->segment, &root->secondary);