Convert sata_sil to new EH.  As these controllers have hardware
interrupt mask and are known to have screaming interrupts issues, use
hardware IRQ masking for freezing.  sil_freeze() masks interrupts for
the port and sil_thaw() unmasks them.  As ports are automatically
frozen before probing reset, there is no need to initialize interrupt
masks sil_init_onde().  Remove related code.

Other than freezing, sata_sil uses stock BMDMA EH routines.
Signed-off-by: Tejun Heo <htejun@gmail.com>