USB: OHCI: ohci-at91: remove unnecessary headers

Remove unnecessary mach/* headers to be able to converge to a multiplatform
kernel.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>