crypto: tcrypt - fix S/G table for test_aead_speed()

crypto: tcrypt - fix S/G table for test_aead_speed()

BugLink: http://bugs.launchpad.net/bugs/1749191
commit 5c6ac1d4f8fbdbed65dbeb8cf149d736409d16a1 upstream.

In case buffer length is a multiple of PAGE_SIZE,
the S/G table is incorrectly generated.
Fix this by handling buflen = k * PAGE_SIZE separately.

Signed-off-by: Robert Baronescu <robert.baronescu@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>