s390: introduce .boot.preserved.data section compile time validation

Same as for .boot.data section make sure that .boot.preserved.data
sections of vmlinux and arch/s390/compressed/vmlinux match before
producing the compressed kernel image. Symbols presence, order and sizes
are cross-checked.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>