MLK-21885 lmb: Handle the overlap case for lmb reserve

MLK-21885 lmb: Handle the overlap case for lmb reserve

lmb reserve is used to reserve some memory so that when loading images
(like kernel, dtb, initrd), images won't be loaded into the reserved memory.

The problem in current lmb is it does not handle the overlap case. When adding
a new reserved memory, if the memory region is overlap with regions already been
added in lmb, it will fail. One example is reserved memory in DTB may overlap with
u-boot relocate address. lmb reserves the u-boot relocate address firstly, so when
adding reserved memory from DTB, we will meet failure.

Actually if we handle the overlap case, we can resolve the overlap by using a max
common region for the overlap regions. So that this case won't fail.

Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>