[x86] Remove heap section from linker.

Heap section in linker was bloating the binary.
Now Xvisor allocats heap memory on the fly so its
not needed.

Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>
Merge pull request #19 from hschauhan/x86-next

[x86] Remove heap section from linker.