x86, build: Fix portability issues when cross-building

It would appear that we never actually generated a correct CRC when
building on a bigendian machine.  Depending on the word size, we would
either generate an all-zero CRC (64-bit machine) or a byte-swapped
CRC (32-bit machine.)  Fix the types used so we don't arbitrarily use
a 64-bit word to hold 32-bit numbers, and pass the CRC through
put_unaligned_le32() like all the other numbers.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Bowler <nbowler@elliptictech.com>
Link: http://lkml.kernel.org/r/20120229111322.9eb4b23ff1672e8853ad3b3b@canb.auug.org.au