arm64: use is_vmalloc_addr

To is_vmalloc_addr() to check if an address is a vmalloc address
instead of checking VMALLOC_START and VMALLOC_END manually.
Signed-off-by: NMiles Chen <miles.chen@mediatek.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

arch/arm64/mm/ioremap.c

@@ -88,7 +88,7 @@ void __iounmap(volatile void __iomem *io_addr)
 	 * We could get an address outside vmalloc range in case
 	 * of ioremap_cache() reusing a RAM mapping.
 	 */
-	if (VMALLOC_START <= addr && addr < VMALLOC_END)
+	if (is_vmalloc_addr((void *)addr))
 		vunmap((void *)addr);
 }
 EXPORT_SYMBOL(__iounmap);