memblock, memhotplug: fix wrong type in memblock_find_in_range_node().

In memblock_find_in_range_node(), we defined ret as int.  But it should
be phys_addr_t because it is used to store the return value from
__memblock_find_range_bottom_up().

The bug has not been triggered because when allocating low memory near
the kernel end, the "int ret" won't turn out to be negative.  When we
started to allocate memory on other nodes, and the "int ret" could be
minus.  Then the kernel will panic.

A simple way to reproduce this: comment out the following code in
numa_init(),

        memblock_set_bottom_up(false);

and the kernel won't boot.

Reported-by: Xishi Qiu <[email protected]>
Signed-off-by: Tang Chen <[email protected]>
Tested-by: Xishi Qiu <[email protected]>
Cc: <[email protected]>	[3.13+]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

mm/memblock.c

@@ -192,8 +192,7 @@ phys_addr_t __init_memblock memblock_find_in_range_node(phys_addr_t size,
 					phys_addr_t align, phys_addr_t start,
 					phys_addr_t end, int nid)
 {
-	int ret;
-	phys_addr_t kernel_end;
+	phys_addr_t kernel_end, ret;
 
 	/* pump up @end */
 	if (end == MEMBLOCK_ALLOC_ACCESSIBLE)