n every encrypted byte. This
patch adds ecb(arc4) directly into arc4.c for higher performance.

tcrypt results (speed ratios: new/old):

AMD Phenom II, x86-64 : x2.7
Intel Core 2, x86-64  : x1.9
Intel Atom N260, i386 : x1.4

Cc: Jon Oberheide <jon@oberheide.org>
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>