ata: ahci_xgene: dereferencing uninitialized pointer in probe

If the call to acpi_get_object_info() fails then "info" hasn't been
initialized.  In that situation, we already know that "version" should
be XGENE_AHCI_V1 so we don't actually need to dereference "info".

Fixes: c9802a4b ('ata: ahci_xgene: Add AHCI Support for 2nd HW version of APM X-Gene SoC AHCI SATA Host controller.')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>