i965: Make uniform offsets be in terms of bytes

i965: Make uniform offsets be in terms of bytes

This commit pushes makes uniform offsets be terms of bytes starting with
nir_lower_io.  They get converted to be in terms of vec4s or floats when we
cram them in the UNIFORM register file but reladdr remains in terms of
bytes all the way down to the point where we lower it to a pull constant
load.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>