iommu/vt-d: Fix an error handling path in 'intel_prepare_irq_remapping()'

If 'intel_cap_audit()' fails, we should return directly, as already done in
the surrounding error handling path.

Fixes: ad3d1902 ("iommu/vt-d: Audit IOMMU Capabilities and add helper functions")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/98d531caabe66012b4fffc7813fd4b9470afd517.1618124777.git.christophe.jaillet@wanadoo.fr


Signed-off-by: Joerg Roedel <jroedel@suse.de>