[SCSI] aacraid: Relax the tight timeout loop on fib commands

The loop that waited for syncronous fib commands was causing a CPU stall
when a timeout actually occured.

1) Switch to using a more accurate timeout mechanism.
2) Do not pace the loop with udelay(). Use cpu_relax() to allow for
   scheduling to occur.

Signed-off-by: Ben Collins <bcollins@ubuntu.com>
Acked-by: Achim Leubner <Achim_Leubner@pmc-sierra.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>