ata: sata_mv: Fix worthy headers and demote others

Fixes the following W=1 kernel build warning(s):

 drivers/ata/sata_mv.c:1162: warning: Function parameter or member 'ap' not described in 'mv_start_edma'
 drivers/ata/sata_mv.c:1162: warning: Function parameter or member 'port_mmio' not described in 'mv_start_edma'
 drivers/ata/sata_mv.c:1162: warning: Function parameter or member 'protocol' not described in 'mv_start_edma'
 drivers/ata/sata_mv.c:1162: warning: Excess function parameter 'base' description in 'mv_start_edma'
 drivers/ata/sata_mv.c:1535: warning: Function parameter or member 'enable_bmdma' not described in 'mv_bmdma_enable_iie'
 drivers/ata/sata_mv.c:1535: warning: expecting prototype for mv_bmdma_enable(). Prototype was for mv_bmdma_enable_iie() instead
 drivers/ata/sata_mv.c:1930: warning: Function parameter or member 'ap' not described in 'mv_bmdma_stop_ap'
 drivers/ata/sata_mv.c:1930: warning: expecting prototype for mv_bmdma_stop(). Prototype was for mv_bmdma_stop_ap() instead
 drivers/ata/sata_mv.c:2228: warning: Function parameter or member 'ap' not described in 'mv_send_fis'
 drivers/ata/sata_mv.c:3263: warning: Function parameter or member 'hpriv' not described in 'mv6_reset_hc'
 drivers/ata/sata_mv.c:3263: warning: Function parameter or member 'n_hc' not described in 'mv6_reset_hc'
 drivers/ata/sata_mv.c:3541: warning: Function parameter or member 'hpriv' not described in 'soc_is_65n'
 drivers/ata/sata_mv.c:3541: warning: expecting prototype for soc_is_65(). Prototype was for soc_is_65n() instead

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Mark Lord <mlord@pobox.com>
Cc: ALWAYS copy <linux-ide@vger.kernel.org>
Cc: linux-ide@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>