xen: fix error handling path if xen_allocate_irq_dynamic fails
xen: fix error handling path if xen_allocate_irq_dynamic fails

It is possible that the call to xen_allocate_irq_dynamic() returns negative
number other than -1.

Reviewed-by: David Vrabel <b9d45bd1f671e508cd8daa63dfc3cabb597562df@citrix.com>
Signed-off-by: Wei Liu <a5240e9e4c4d742e3a4232ca749f78defd45d722@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <da3a51b335cef0eb0e2c329c5ef6bcd6acef687a@oracle.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas