1. define "struct ssp_device" for SSP information, which is requested
   and released by function ssp_request()/ssp_free()

2. modify the ssp_init() and ssp_exit() to use the interface
Signed-off-by: Neric miao <eric.miao@marvell.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>