staging: r8188eu: Additional cleanup of include/odm.h

This driver only works with the USB bus. Accordingly, enum odm_interface_def
can be removed along with all code that uses ODM_ITRF_XXX, where XXX is not USB.

In enum odm_ic_type, only ODM_RTL8188E is used. Remove the enum, all references
to the others, and define the needed value.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>