scsi: SCSI_ISCI needs to select SCSI_SAS_HOST_SMP, fixes build error

SCSI_ISCI needs to select SCSI_SAS_HOST_SMP to ensure that all
needed symbols are available to it.

Fixes this build error:

  ERROR: "try_test_sas_gpio_gp_bit" [drivers/scsi/isci/isci.ko] undefined!

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>