i2c: qup: Add missing unwind goto in qup_i2c_probe()

Smatch Warns:
	drivers/i2c/busses/i2c-qup.c:1784 qup_i2c_probe()
	warn: missing unwind goto?

The goto label "fail_runtime" and "fail" will disable qup->pclk,
but here qup->pclk failed to obtain, in order to be consistent,
change the direct return to goto label "fail_dma".

Fixes: 9cedf3b2

 ("i2c: qup: Add bam dma capabilities")
Signed-off-by: Shuai Jiang <d202180596@hust.edu.cn>
Reviewed-by: Dongliang Mu <dzm91@hust.edu.cn>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Cc: <stable@vger.kernel.org> # v4.6+