crypto: cavium - Fix the if condition to exit loop after timeout

The while loop breaks in the first run because of incorrect
if condition. It also causes the statements after the if to
appear dead.
Fix this by changing the condition from if(timeout--) to
if(!timeout--).

This bug was reported by Coverity Scan.
Report:
CID 1600859: (#1 of 1): Logically dead code (DEADCODE)
dead_error_line: Execution cannot reach this statement: udelay(30UL);

Fixes: 9e2c7d99 ("crypto: cavium - Add Support for Octeon-tx CPT Engine")
Signed-off-by: Everest K.C. <everestkc@everestkc.com.np>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>