nvram_compress() and zip_oops() is used by the nvram_pstore_write
API to compress oops messages hence re-organise the functions
accordingly to avoid forward declarations.
Signed-off-by: NAruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>