meta-ibm: add IBMBASE

Define a variable that recipes can use for finding the root
of the ibm layer.  Typically this is used to refer to the
layer LICENSE for recipes that don't have any source repository.

Change-Id: I049425e94a5cafbe0392b38180db8f70d25d838f
Signed-off-by: Patrick Venture <venture@google.com>
1 file changed