crypto: ecc - Silence sparse warning

Rewrite the bitwise operations to silence the sparse warnings:

  CHECK   ../crypto/ecc.c
../crypto/ecc.c:1387:39: warning: dubious: !x | y
../crypto/ecc.c:1397:47: warning: dubious: !x | y

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Vitaly Chikunov <vt@altlinux.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>