Compute the vmlinux size at runtime.

Use Z_FULL_FLUSH instead of Z_FINISH, to extract only the ELF header
and ELF program header.

 ->p_memsz is the required memory range for the executable, including bss
 ->p_filesz is the size of .text, .data and other runtime sections

These values must be used for the claim call.
All additional memory needed by the kernel is claimed in prom_init, remove
the extra Mb.

Pass the full memsize as target area to gunzip, otherwise not everything
will be uncompressed.

flush_cache has to flush all runtime sections, do not reduce the memrange
by the ->p_offset value because its just that: an offset.

Remove the Makefile code to produce an imagesize.c, its not needed anymore.
Remove all FORCE flags, to not rebuild the zImage if vmlinux was not changed.
Signed-off-by: Olaf Hering <olh@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>