mt7601u: remove a warning in mt7601u_efuse_physical_size_check()

Fix the following sparse warning in mt7601u_efuse_physical_size_check:
- drivers/net/wireless/mediatek/mt7601u/eeprom.c:77:27: warning:
  Variable length array is used

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Acked-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/mediatek/mt7601u/eeprom.c

@@ -75,7 +75,7 @@ static int
 mt7601u_efuse_physical_size_check(struct mt7601u_dev *dev)
 {
 	const int map_reads = DIV_ROUND_UP(MT_EFUSE_USAGE_MAP_SIZE, 16);
-	u8 data[map_reads * 16];
+	u8 data[round_up(MT_EFUSE_USAGE_MAP_SIZE, 16)];
 	int ret, i;
 	u32 start = 0, end = 0, cnt_free;