glsl: move variables in to ir_variable::data, part II

glsl: move variables in to ir_variable::data, part II

This patch moves following bitfields and variables to the data
structure:

explicit_location, explicit_index, explicit_binding, has_initializer,
is_unmatched_generic_inout, location_frac, from_named_ifc_block_nonarray,
from_named_ifc_block_array, depth_layout, location, index, binding,
max_array_access, atomic

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Paul Berry <stereotype441@gmail.com>