lmb: make LMB memory map persistent and global

The current LMB API's for allocating and reserving memory use a
per-caller based memory view. Memory allocated by a caller can then be
overwritten by another caller. Make these allocations and reservations
persistent using the alloced list data structure.

Two alloced lists are declared -- one for the available(free) memory,
and one for the used memory. Once full, the list can then be extended
at runtime.

[sjg: Use a stack to store pointer of lmb struct when running lmb tests]

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
[sjg: Optimise the logic to add a region in lmb_add_region_flags()]

arch/arm/lib/stack.c

@@ -42,7 +42,7 @@ static ulong get_sp(void)
 	return ret;
 }
 
-void arch_lmb_reserve(struct lmb *lmb)
+void arch_lmb_reserve(void)
 {
-	arch_lmb_reserve_generic(lmb, get_sp(), gd->ram_top, 16384);
+	arch_lmb_reserve_generic(get_sp(), gd->ram_top, 16384);
 }