genxml: Make 1-bit L3$ config register fields bool on Gen7
Otherwise, they look like booleans but, if you put a value other than 0/1 in them, the GenXML generator code will explode.
Fixes: b6875b00 "anv: Drop has_slm in emit_l3_config for gen11+"
Otherwise, they look like booleans but, if you put a value other than 0/1 in them, the GenXML generator code will explode.
Fixes: b6875b00 "anv: Drop has_slm in emit_l3_config for gen11+"