drm/amd/display: use ARRAY_SIZE for base60_refresh_rates

Use ARRAY_SIZE instead of dividing sizeof array with sizeof an
element.

Clean up the following coccicheck warning:

./drivers/gpu/drm/amd/display/dc/core/dc_resource.c:448:47-48: WARNING:
Use ARRAY_SIZE.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_resource.c

@@ -445,7 +445,7 @@ bool resource_are_vblanks_synchronizable(
 {
 	uint32_t base60_refresh_rates[] = {10, 20, 5};
 	uint8_t i;
-	uint8_t rr_count = sizeof(base60_refresh_rates)/sizeof(base60_refresh_rates[0]);
+	uint8_t rr_count = ARRAY_SIZE(base60_refresh_rates);
 	uint64_t frame_time_diff;
 
 	if (stream1->ctx->dc->config.vblank_alignment_dto_params &&