USB: EHCI: fix build error in ChipIdea host driver

This patch (as1629) fixes a build error in the ChipIdea host driver
when compiled for the ARM architecture.  The error was introduced
by commit 99f91934a907df31ba878dfdd090002049dc476a (USB: EHCI: make
ehci-platform a separate driver).

The fix is simple; an additional header-file #include is needed.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>