x86: link: Increase malloc size and decrease code size

At present link does not boot since it has outgrown its pre-relocation
malloc() size and its assigned code area. Increase the former and drop
EFI loader support, which adds about 45KB!

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>