it assumes we have an unaligned exception handler which

 (a) may not be true
 (b) costs a lot of performance
 Instead we'll use struct/union method for big endian accesses,
  and byte-shifting for little endian.

Signed-off-by: John Williams <john.williams@petalogix.com>

Reviewed-by: Ingo Molnar <mingo@elte.hu>
Acked-by: John Linn <john.linn@xilinx.com>
Acked-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Acked-by: John Williams <john.williams@petalogix.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>