arm64: fix the flush_icache_range arguments in machine_kexec

The second argument is the end "pointer", not the length.

Fixes: d28f6df ("arm64/kexec: Add core kexec support")
Cc: <stable@vger.kernel.org> # 4.8.x-
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/kernel/machine_kexec.c

@@ -177,6 +177,7 @@ void machine_kexec(struct kimage *kimage)
 	 * the offline CPUs. Therefore, we must use the __* variant here.
 	 */
 	__flush_icache_range((uintptr_t)reboot_code_buffer,
+			     (uintptr_t)reboot_code_buffer +
 			     arm64_relocate_new_kernel_size);
 
 	/* Flush the kimage list and its buffers. */