usb: ohci: nxp: clean up included header files

Remove mach/irq.h from the list of included headers, there is no
compilation dependency on this include file, the change is needed
to prevent a compilation failure, when mach/irq.h is removed.

Additionally remove other unneeded includes.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>