ARM: Kirkwood: Fix 'SZ_1M' undeclared here for db88f6281-bp-setup.c

Linux-next has failed to compile for kirkwood since 23 August with:

arch/arm/mach-kirkwood/db88f6281-bp-setup.c:29: error: 'SZ_1M' undeclared here (not in a function)
arch/arm/mach-kirkwood/db88f6281-bp-setup.c:33: error: 'SZ_4M' undeclared here (not in a function)

Add missing <linux/sizes.h>
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJason Cooper <jason@lakedaemon.net>

arch/arm/mach-kirkwood/db88f6281-bp-setup.c

@@ -10,6 +10,7 @@
 
 #include <linux/kernel.h>
 #include <linux/init.h>
+#include <linux/sizes.h>
 #include <linux/platform_device.h>
 #include <linux/mtd/partitions.h>
 #include <linux/ata_platform.h>