[POWERPC] Split initrd logic out of early_init_dt_scan_chosen() to fix warning

If CONFIG_BLK_DEV_INITRD is not defined the prop variable in
early_init_dt_scan_chosen() is unused, causing a compiler warning.

So split the initrd logic into a separate function, allowing us to
declare prop only when we need it.

Built for both cases and booted with an initrd.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/prom.c

@@ -716,11 +716,40 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
 	return 0;
 }
 
+#ifdef CONFIG_BLK_DEV_INITRD
+static void __init early_init_dt_check_for_initrd(unsigned long node)
+{
+	unsigned long l;
+	u32 *prop;
+
+	DBG("Looking for initrd properties... ");
+
+	prop = of_get_flat_dt_prop(node, "linux,initrd-start", &l);
+	if (prop) {
+		initrd_start = (unsigned long)__va(of_read_ulong(prop, l/4));
+
+		prop = of_get_flat_dt_prop(node, "linux,initrd-end", &l);
+		if (prop) {
+			initrd_end = (unsigned long)
+					__va(of_read_ulong(prop, l/4));
+			initrd_below_start_ok = 1;
+		} else {
+			initrd_start = 0;
+		}
+	}
+
+	DBG("initrd_start=0x%lx  initrd_end=0x%lx\n", initrd_start, initrd_end);
+}
+#else
+static inline void early_init_dt_check_for_initrd(unsigned long node)
+{
+}
+#endif /* CONFIG_BLK_DEV_INITRD */
+
 static int __init early_init_dt_scan_chosen(unsigned long node,
 					    const char *uname, int depth, void *data)
 {
 	unsigned long *lprop;
-	u32 *prop;
 	unsigned long l;
 	char *p;
 
@@ -762,21 +791,7 @@ static int __init early_init_dt_scan_chosen(unsigned long node,
                crashk_res.end = crashk_res.start + *lprop - 1;
 #endif
 
-#ifdef CONFIG_BLK_DEV_INITRD
-	DBG("Looking for initrd properties... ");
-	prop = of_get_flat_dt_prop(node, "linux,initrd-start", &l);
-	if (prop) {
-		initrd_start = (unsigned long)__va(of_read_ulong(prop, l/4));
-		prop = of_get_flat_dt_prop(node, "linux,initrd-end", &l);
-		if (prop) {
-			initrd_end = (unsigned long)__va(of_read_ulong(prop, l/4));
-			initrd_below_start_ok = 1;
-		} else {
-			initrd_start = 0;
-		}
-	}
-	DBG("initrd_start=0x%lx  initrd_end=0x%lx\n", initrd_start, initrd_end);
-#endif /* CONFIG_BLK_DEV_INITRD */
+	early_init_dt_check_for_initrd(node);
 
 	/* Retreive command line */
  	p = of_get_flat_dt_prop(node, "bootargs", &l);