usb: musb: Makefile: remove unexistent config option

Remove the unexistent CONFIG_USB_INVENTRA_MUSB_HAS_AHB_ID
option from our Makefile.

Problem reported by Sergei Shtylyov <sshtylyov@mvista.com>

Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>