ppc64: Fix a typo in the code that reserves memory at boot

Hi !

The code that marks memory regions as "reserved" early during boot has a typo (doing incorrect rounding of the top address) which can cause some areas to not be properly reserved. That may explain some cases of initrd corruption reported recently.

===== arch/ppc64/kernel/prom_init.c 1.2 vs edited =====

@@ -595,7 +595,7 @@
 	 * dumb and just copy this entire array to the boot params
 	 */
 	base = _ALIGN_DOWN(base, PAGE_SIZE);
-	top = _ALIGN_DOWN(top, PAGE_SIZE);
+	top = _ALIGN_UP(top, PAGE_SIZE);
 	size = top - base;
 
 	if (cnt >= (MEM_RESERVE_MAP_SIZE - 1))

Ok, ignore it and take Anton's one instead.

Ben.