ARM: 7941/2: Fix incorrect FDT initrd parameter override

Commit 65939301 (arm: set initrd_start/initrd_end for fdt scan)
caused the FDT initrd_start and initrd_end to override the
phys_initrd_start and phys_initrd_size set by the initrd= kernel
parameter.  With this patch initrd_start and initrd_end will be
overridden if phys_initrd_start and phys_initrd_size are set by the
kernel initrd= parameter.

Fixes: 65939301 (arm: set initrd_start/initrd_end for fdt scan)
Signed-off-by: NBen Peddell <klightspeed@killerwolves.net>
Acked-by: NJason Cooper <jason@lakedaemon.net>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/init.c

@@ -345,10 +345,11 @@ void __init arm_memblock_init(struct meminfo *mi,
 #endif
 #ifdef CONFIG_BLK_DEV_INITRD
 	/* FDT scan will populate initrd_start */
-	if (initrd_start) {
+	if (initrd_start && !phys_initrd_size) {
 		phys_initrd_start = __virt_to_phys(initrd_start);
 		phys_initrd_size = initrd_end - initrd_start;
 	}
+	initrd_start = initrd_end = 0;
 	if (phys_initrd_size &&
 	    !memblock_is_region_memory(phys_initrd_start, phys_initrd_size)) {
 		pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",