x86/mm/gart: Drop unnecessary check

The memblock_find_in_range() return value addr is guaranteed
to be within "addr + aper_size" and not beyond GART_MAX_ADDR.
Signed-off-by: Wang YanQing <udknight@gmail.com>
Cc: yinghai@kernel.org
Link: http://lkml.kernel.org/r/20130416013734.GA14641@udknightSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/aperture_64.c

@@ -87,7 +87,7 @@ static u32 __init allocate_aperture(void)
 	 */
 	addr = memblock_find_in_range(GART_MIN_ADDR, GART_MAX_ADDR,
 				      aper_size, aper_size);
-	if (!addr || addr + aper_size > GART_MAX_ADDR) {
+	if (!addr) {
 		printk(KERN_ERR
 			"Cannot allocate aperture memory hole (%lx,%uK)\n",
 				addr, aper_size>>10);