scsi: mvsas: Mark symbols static where possible

We get a few warnings when building kernel with W=1:
drivers/scsi/mvsas/mv_sas.c:77:18: warning: no previous prototype for 'mvs_find_dev_mvi' [-Wmissing-prototypes]
drivers/scsi/mvsas/mv_sas.c:105:5: warning: no previous prototype for 'mvs_find_dev_phyno' [-Wmissing-prototypes]
drivers/scsi/mvsas/mv_sas.c:1161:20: warning: no previous prototype for 'mvs_alloc_dev' [-Wmissing-prototypes]
drivers/scsi/mvsas/mv_sas.c:1178:6: warning: no previous prototype for 'mvs_free_dev' [-Wmissing-prototypes]
drivers/scsi/mvsas/mv_sas.c:1188:5: warning: no previous prototype for 'mvs_dev_found_notify' [-Wmissing-prototypes]
drivers/scsi/mvsas/mv_sas.c:1244:6: warning: no previous prototype for 'mvs_dev_gone_notify' [-Wmissing-prototypes]
drivers/scsi/mvsas/mv_sas.c:1614:6: warning: no previous prototype for 'mvs_set_sense' [-Wmissing-prototypes]
drivers/scsi/mvsas/mv_sas.c:1653:6: warning: no previous prototype for 'mvs_fill_ssp_resp_iu' [-Wmissing-prototypes]
drivers/scsi/mvsas/mv_64xx.c:139:6: warning: no previous prototype for 'mvs_64xx_clear_srs_irq' [-Wmissing-prototypes]
drivers/scsi/mvsas/mv_64xx.c:566:6: warning: no previous prototype for 'mvs_64xx_make_prd' [-Wmissing-prototypes]
....

In fact, these functions are only used in the file in which they are
declared and don't need a declaration, but can be made static.  So this
patch marks these functions with 'static'.

Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>