Revert "USB: ncm: added ncm.h with auxiliary definitions"

This reverts commit 65e0b499.

Since the host and gadget implementations are different, there is
no common code for the file, remove for now.

Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>