intel: initialize fs_visitor::params_remap in constructor

Set fs_visitor::params_remap to NULL in the constructor.
This variable was potentially tested in fs_visitor::remove_dead_constants()
before being set.

NOTE: This is a candidate for stable release branches.

Signed-off-by: Frank Henigman <fjhenigman@google.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

src/mesa/drivers/dri/i965/brw_fs_visitor.cpp

@@ -2463,6 +2463,8 @@ fs_visitor::fs_visitor(struct brw_context *brw,
    this->virtual_grf_end = NULL;
    this->live_intervals_valid = false;
 
+   this->params_remap = NULL;
+
    this->force_uncompressed_stack = 0;
    this->force_sechalf_stack = 0;