ppc/pnv: add INITRD_MAX_SIZE constant

The current 0x10000000 value is actually 256MiB, not 128MB as the comment
suggests. Move it to a constant and fix the comment (no change in the size
value).

Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Message-Id: <20190225170155.1972-3-muriloo@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

hw/ppc/pnv.c

@@ -56,6 +56,7 @@
 #define KERNEL_LOAD_ADDR        0x20000000
 #define KERNEL_MAX_SIZE         (256 * MiB)
 #define INITRD_LOAD_ADDR        0x60000000
+#define INITRD_MAX_SIZE         (256 * MiB)
 
 static const char *pnv_chip_core_typename(const PnvChip *o)
 {
@@ -601,7 +602,7 @@ static void pnv_init(MachineState *machine)
     if (machine->initrd_filename) {
         pnv->initrd_base = INITRD_LOAD_ADDR;
         pnv->initrd_size = load_image_targphys(machine->initrd_filename,
-                                  pnv->initrd_base, 0x10000000); /* 128MB max */
+                                  pnv->initrd_base, INITRD_MAX_SIZE);
         if (pnv->initrd_size < 0) {
             error_report("Could not load initial ram disk '%s'",
                          machine->initrd_filename);