i965/fs: Properly initialize the livein/liveout sets.

i965/fs: Properly initialize the livein/liveout sets.

Previously, livein was initialized to 0 for all blocks.  According to
the textbook, it should be the universal set (~0) for all blocks except
the one representing the start of the program (which should be 0).

liveout also needs to be initialized to COPY for the initial block.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Paul Berry <stereotype441@gmail.com>