[SCSI] qla2xxx: Fix __LITTLE_ENDIAN definition warnings

On ppc64, gcc 4.4 spews lots of..

drivers/scsi/qla2xxx/qla_def.h:1485:7: warning: "__LITTLE_ENDIAN" is not defined

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>