crypto: testmgr - Fix error flow of test_comp

This warning:

  crypto/testmgr.c: In function ‘test_comp’:
  crypto/testmgr.c:829: warning: ‘ret’ may be used uninitialized in this function

triggers because GCC correctly notices that in the ctcount == 0 &&
dtcount != 0 input condition case this function can return an undefined
value, if the second loop fails.

Remove the shadowed 'ret' variable from the second loop that was probably
unintended.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>