[SCSI] libsas: check for 'gone' expanders in smp_execute_task()
[SCSI] libsas: check for 'gone' expanders in smp_execute_task()

No sense in issuing or retrying commands to an expander that has been
removed.

Signed-off-by: Dan Williams <24ee2bf0bd8ac766c348bf1f0639943bac1535c6@intel.com>
Signed-off-by: James Bottomley <1acebbdca565c7b6b638bdc23b58b5610d1a56b8@Parallels.com>

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