x86: revert wrong memblock current limit setting

x86: revert wrong memblock current limit setting

Dave reported big numa system booting is broken.

It turns out that commit 5b6e529521d3 ("x86: memblock: set current limit
to max low memory address") sets the limit to low wrongly.

max_low_pfn_mapped is different from max_pfn_mapped.
max_low_pfn_mapped is always under 4G.

That will memblock_alloc_nid all go under 4G.

Revert 5b6e529521d3 to fix a no-boot regression which was triggered by
457ff1de2d24 ("lib/swiotlb.c: use memblock apis for early memory
allocations").

Signed-off-by: Yinghai Lu <[email protected]>
Reported-by: Dave Hansen <[email protected]>
Acked-by: Santosh Shilimkar <[email protected]>
Cc: Russell King <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>