iommu/irq_remapping: Refine function irq_remapping_prepare() for maintenance
iommu/irq_remapping: Refine function irq_remapping_prepare() for maintenance

Assign intel_irq_remap_ops to remap_ops only if
intel_irq_remap_ops.prepare() succeeds.

Signed-off-by: Jiang Liu <68ee766e574f18b34b683085865827393efe88bd@linux.intel.com>
Tested-by: Joerg Roedel <4688a6871ff025801033b3c4b039d55a29f8f937@8bytes.org>
Cc: Tony Luck <e7984595ec0368ff920a7b3521dc7093683f6f26@intel.com>
Cc: d4d3187dbcba3fb2e2e25a4ce499c8e441b6817d@lists.linux-foundation.org
Cc: Benjamin Herrenschmidt <a7089bb6e7e92505d88aaff006cbdd60cc9120b6@kernel.crashing.org>
Cc: Yinghai Lu <0674548f4d596393408a51d6287a76ebba2f42aa@kernel.org>
Cc: Borislav Petkov <0691a664b24b6f15b20cd5aee64b72271db08be1@alien8.de>
Link: http://lkml.kernel.org/r/1420615903-28253-15-git-send-email-68ee766e574f18b34b683085865827393efe88bd@linux.intel.com
Signed-off-by: Thomas Gleixner <00e4cf8f46a57000a44449bf9dd8cbbcc209fd2a@linutronix.de>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs