r300: Enable generation of fcsel_gt and fcsel_ge opcodes

RV530:
total instructions in shared programs: 135032 -> 134833 (-0.15%)
instructions in affected programs: 15654 -> 15455 (-1.27%)
helped: 133
HURT: 13

total temps in shared programs: 17051 -> 17045 (-0.04%)
temps in affected programs: 202 -> 196 (-2.97%)
helped: 11
HURT: 5

RV370:
total instructions in shared programs: 84439 -> 84378 (-0.07%)
instructions in affected programs: 2519 -> 2458 (-2.42%)
helped: 49
HURT: 7

total temps in shared programs: 12399 -> 12380 (-0.15%)
temps in affected programs: 322 -> 303 (-5.90%)
helped: 20
HURT: 10

GAINED: shaders/godot3.4/22-69.shader_test FS

Reviewed-by: Emma Anholt <emma@anholt.net>
Reviewed-by: Pavel Ondračka <pavel.ondracka@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20162>

src/gallium/drivers/r300/r300_screen.c

@@ -525,6 +525,7 @@ static const nir_shader_compiler_options r500_vs_compiler_options = {
 static const nir_shader_compiler_options r500_fs_compiler_options = {
    COMMON_NIR_OPTIONS,
    .lower_fpow = true, /* POW is only in the VS */
+   .has_fused_comp_and_csel = true,
 
    /* Have HW loops support and 512 max instr count, but don't unroll *too*
     * hard.
@@ -545,6 +546,7 @@ static const nir_shader_compiler_options r300_fs_compiler_options = {
    COMMON_NIR_OPTIONS,
    .lower_fpow = true, /* POW is only in the VS */
    .lower_sincos = true,
+   .has_fused_comp_and_csel = true,
 
     /* No HW loops support, so set it equal to ALU instr max */
    .max_unroll_iterations = 64,