x86: fix memalign() parameter order

Purely by code inspection, it looks like the parameter order to memalign()
is swapped; its parameters are (align, size). 4096 is a likely desired
alignment, and a variable named size sounds like a size:-)

Fixes: 45b5a378 ("x86: Add multi-processor init")
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Bin Meng <bmeng.cn@gmail.com>