ata: sata_mv: aspeed: fix value check in mv_platform_probe()

In mv_platform_probe(), check the return value of clk_prepare_enable()
and return the error code if clk_prepare_enable() returns an
unexpected value.

Signed-off-by: Ma Ke <make_ruc2021@163.com>
Reviewed-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>