drm/amd/pm: vega10_hwmgr: fix potential off-by-one overflow in 'performance_levels'

Since 'hardwareActivityPerformanceLevels' is set to the size of the
'performance_levels' array in vega10_hwmgr_backend_init(), using the
'<=' assertion to check for the next index value is incorrect.
Replace it with '<'.

Detected using the static analysis tool - Svace.
Fixes: f83a9991 ("drm/amd/powerplay: add Vega10 powerplay support (v5)")
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alexey Kodanev <aleksei.kodanev@bell-sw.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/powerplay/hwmgr/vega10_hwmgr.c

@@ -3155,7 +3155,7 @@ static int vega10_get_pp_table_entry_callback_func(struct pp_hwmgr *hwmgr,
 			return -1);
 
 	PP_ASSERT_WITH_CODE(
-			(vega10_ps->performance_level_count <=
+			(vega10_ps->performance_level_count <
 					hwmgr->platform_descriptor.
 					hardwareActivityPerformanceLevels),
 			"Performance levels exceeds Driver limit!",