drm/amd/pm: smu7_hwmgr: fix potential off-by-one overflow in 'performance_levels'

Since 'hardwareActivityPerformanceLevels' is set to the size of the
'performance_levels' array in smu7_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: 599a7e9fe1b6 ("drm/amd/powerplay: implement smu7 hwmgr to manager asics with smu ip version 7.")
Reviewed-by: Evan Quan <[e-mail]>
Signed-off-by: Alexey Kodanev <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_hwmgr.c

···
 			return -EINVAL);
 
 	PP_ASSERT_WITH_CODE(
-			(smu7_power_state->performance_level_count <=
+			(smu7_power_state->performance_level_count <
 					hwmgr->platform_descriptor.hardwareActivityPerformanceLevels),
 			"Performance levels exceeds Driver limit!",
 			return -EINVAL);