drm/amdgpu/display: fix integer arithmetic problem

gcc warns about an ambiguous integer calculation:

drivers/gpu/drm/amd/amdgpu/../display/dc/calcs/dce_calcs.c: In function 'calculate_bandwidth':
drivers/gpu/drm/amd/amdgpu/../display/dc/calcs/dce_calcs.c:534:5: error: this decimal constant is unsigned only in ISO C90 [-Werror]
     data->lb_line_pitch = bw_ceil2(bw_mul(bw_div(bw_frc_to_fixed(2401171875, 100000000), bw_int_to_fixed(3)), bw_ceil2(data->source_width_in_lb, bw_int_to_fixed(8))), bw_int_to_fixed(48));
     ^~~~

Marking the constant as explicitly unsigned makes it work fine everywhere
without warnings.
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/calcs/dce_calcs.c

@@ -531,7 +531,7 @@ static void calculate_bandwidth(
 			}
 			switch (data->lb_bpc[i]) {
 			case 8:
-				data->lb_line_pitch = bw_ceil2(bw_mul(bw_div(bw_frc_to_fixed(2401171875, 100000000), bw_int_to_fixed(3)), bw_ceil2(data->source_width_in_lb, bw_int_to_fixed(8))), bw_int_to_fixed(48));
+				data->lb_line_pitch = bw_ceil2(bw_mul(bw_div(bw_frc_to_fixed(2401171875ul, 100000000), bw_int_to_fixed(3)), bw_ceil2(data->source_width_in_lb, bw_int_to_fixed(8))), bw_int_to_fixed(48));
 				break;
 			case 10:
 				data->lb_line_pitch = bw_ceil2(bw_mul(bw_div(bw_frc_to_fixed(300234375, 10000000), bw_int_to_fixed(3)), bw_ceil2(data->source_width_in_lb, bw_int_to_fixed(8))), bw_int_to_fixed(48));