wifi: mt76: mt7915: workaround too long expansion sparse warnings

Fix the following sparse warnings:

drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c:1133:29: error: too long token expansion
drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c:1133:29: error: too long token expansion
drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c:1133:29: error: too long token expansion
drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c:1133:29: error: too long token expansion

No functional changes, compile tested only.

Fixes: e3296759

 ("wifi: mt76: mt7915: enable per bandwidth power limit support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/5457b92e41909dd75ab3db7a0e9ec372b917a386.1710858172.git.lorenzo@kernel.org