Added the suspend/resume support to ctxfi driver.

The team tested on the following seems ok:
  AMD Athlon 64 3500+ / ASUS A8N-E / 512MB DDR ATI / Radeon X1300
  20k1 & 20k2 cards
Signed-off-by: NWai Yew CHAY <wychay@ctl.creative.com>
Singed-off-by: NRyan RICHARDS <ryan_richards@creativelabs.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>