This patch fixes a efi_memmap overflow problem on large system.
Currently the kexec allocates statically 16k buffer to contain
efi_memmap. It can hold about 333 entries. It causes data
corruption on large system.

This patch would let kexec allocate the efi_memmap at run time using
the actual size allocated in the production kernel.


Signed-off-by: Jay Lan <jlan@sgi.com>