USB: Remove __attribute__ ((packed)) for struct ehci_hccr and ehci_hcor

Remove __attribute__ ((packed)) to prevent byte access to soc
registers in some gcc versions.

Having patches to enable ehci for the BeagleBoard lying around for
several months, this one was the show-stopper.

Switched to align(4), rather than remove the attribute, per suggestion
from Alexander.

Credits have to go to Laine Walker-Avina <lwalkera@ieee.org> for
finding the problem.

Signed-off-by: Jason Kridner <jkridner@beagleboard.org>
Signed-off-by: Joel A Fernandes <agnel.joel@gmail.com>
Cc: Alexander Holler <holler@ahsoftware.de>
Cc: Sandeep Paulraj <s-paulraj@ti.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>