nir: silence a couple new compiler warnings

nir: silence a couple new compiler warnings

[33/630] Compiling C object 'src/compiler/nir/nir@sta/nir_loop_analyze.c.o'.
../src/compiler/nir/nir_loop_analyze.c: In function ‘try_find_trip_count_vars_in_iand’:
../src/compiler/nir/nir_loop_analyze.c:846:29: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
    if (*ind == NULL || *ind && (*ind)->type != basic_induction ||
                             ^
[85/630] Compiling C object 'src/compiler/nir/nir@sta/nir_opt_loop_unroll.c.o'.
../src/compiler/nir/nir_opt_loop_unroll.c: In function ‘complex_unroll_single_terminator’:
../src/compiler/nir/nir_opt_loop_unroll.c:494:17: warning: unused variable ‘unroll_loc’ [-Wunused-variable]
    nir_cf_node *unroll_loc =
                 ^
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>