[][MAC80211][mt76][wifi: mt76: mt7915: rework mt7915_thermal_init]

[Description]
Fix mt7915_thermal_init() to initialize critial/maximum temperature if
CONFIG_HWMON is N.

[Release-log]
N/A

Change-Id: I4a3421c6b82775318b621dd34441eb63c5fd665e
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/7066694
1 file changed