drivers/clk/mediatek: suspected missing null check for return pointer of mtk_alloc_clk_data

[YE Chengfeng]

Hi,

https://github.com/torvalds/linux/blob/master/drivers/clk/mediatek/clk-mt7622.c#L622

The return pointer of mtk_alloc_clk_data could be null, but null check is missing. It seems like there could be a potential null-pointer dereference problem at #line 639 and so on. Would you like to spare some time to have a look at it?

Thanks so much,
Chengfeng