ata: ahci_imx: Fix error code in probe()

Return a negative error code if devm_clk_get() fails.  Don't return
success.

Fixes: 3156e1b2 ("ata: ahci_imx: AHB clock rate setting is not required on i.MX8QM AHCI SATA")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/cbcbdfc2-ddc7-4684-8ad4-018227823546@stanley.mountain


Signed-off-by: Niklas Cassel <cassel@kernel.org>