greybus: endo: move endo id map declaration to endo.h

There is a sparse warning. The endo id map is also
used in endo.c. Should define in endo.h

Signed-off-by: Phong Tran <tranmanphong@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>