[POWERPC] U-boot passes the initrd as start/end, not start/size.

The boot wrapper platform init code on 83xx and 85xx using the cuboot
platform type was incorrectly assuming that u-boot supplied the size
of the initrd, whereas it actually supplies the end address.  This
fixes it.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/boot/cuboot-83xx.c

@@ -57,7 +57,7 @@ void platform_init(unsigned long r3, unsigned long r4, unsigned long r5,
 
 	memcpy(&bd, (bd_t *)r3, sizeof(bd));
 	loader_info.initrd_addr = r4;
-	loader_info.initrd_size = r4 ? r5 : 0;
+	loader_info.initrd_size = r4 ? r5 - r4 : 0;
 	loader_info.cmdline = (char *)r6;
 	loader_info.cmdline_len = r7 - r6;
 

arch/powerpc/boot/cuboot-85xx.c

@@ -58,7 +58,7 @@ void platform_init(unsigned long r3, unsigned long r4, unsigned long r5,
 
 	memcpy(&bd, (bd_t *)r3, sizeof(bd));
 	loader_info.initrd_addr = r4;
-	loader_info.initrd_size = r4 ? r5 : 0;
+	loader_info.initrd_size = r4 ? r5 - r4 : 0;
 	loader_info.cmdline = (char *)r6;
 	loader_info.cmdline_len = r7 - r6;