[SCSI] qla2xxx: Refactor call to qla2xxx_read_sfp for thermal temperature.

Eliminate duplicate code by refactoring the calls to qla2xxx_read_sfp()
in qla2x00_get_thermal_temp(). This keeps the parameter values separate
from the mailbox register mechanics. This also allows qla2xxx_read_sfp()
to be the sole "spec" for READ SFP semantics.

Signed-off_by: Joe Carnuccio <joe.carnuccio@qlogic.com>
Signed-off-by: Madhuranath Iyengar <Madhu.Iyengar@qlogic.com>
Signed-off-by: James Bottomley <jbottomley@parallels.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>