memblock: check memory total_size

mem=[X][G|M] is broken on ARM64 platform, there are cases that even
type.cnt is 1, but total_size is not 0 because regions are merged into
1.  So only check 'cnt' is not enough, total_size should be used,
othersize bootargs 'mem=[X][G|B]' not work anymore.

Link: https://lkml.kernel.org/r/20210930024437.32598-1-peng.fan@oss.nxp.com
Fixes: e888fa7b ("memblock: Check memory add/cap ordering")
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memblock.c

@@ -1692,7 +1692,7 @@ void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size)
 	if (!size)
 		return;
 
-	if (memblock.memory.cnt <= 1) {
+	if (!memblock_memory->total_size) {
 		pr_warn("%s: No memory registered yet\n", __func__);
 		return;
 	}