usb: host: ehci: fix missing kfree in remove path also

Added missing kfree() in ehci_hcd_omap_remove().

Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>