fix CONFIG_SATA_SIS=y compile error

Static code shouldn't be used from other modules.

drivers/built-in.o: In function `sis_init_one':
sata_sis.c:(.text+0x7634cd): undefined reference to `sis_info133'
sata_sis.c:(.text+0x7634d6): undefined reference to `sis_info133'

While I was at it, I also moved the prototype of this struct to a header
file.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>