ieee1394: sbp2: fix spindown for PL-3507 and TSB42AA9 firmwares

Reported by Tino Keitel:  PL-3507 with firmware from Prolific does not
spin down the disk on START STOP UNIT with power condition = 0 and start
= 0.  It does however work with power condition = 2 or 3.

Also found while investigating this:  DViCO Momobay CX-1 and FX-3A (TI
TSB42AA9/A based) become unresponsive after START STOP UNIT with power
condition = 0 and start = 0.  They stay responsive if power condition is
set when stopping the motor.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

drivers/ieee1394/sbp2.h

@@ -345,6 +345,7 @@ enum sbp2lu_state_types {
 #define SBP2_WORKAROUND_FIX_CAPACITY	0x8
 #define SBP2_WORKAROUND_DELAY_INQUIRY	0x10
 #define SBP2_INQUIRY_DELAY		12
+#define SBP2_WORKAROUND_POWER_CONDITION	0x20
 #define SBP2_WORKAROUND_OVERRIDE	0x100
 
 #endif /* SBP2_H */