This change allows quering for variables with the format A_B, i.e.
PREFERRED_PROVIDER_virtual/kernel instead of just A.
(From OE-Core rev: 3810738eff6bdcf27c7e291dbeaedc699ab14bfc)
Signed-off-by: Leonardo Sandoval <leonardo.sandoval.gonzalez@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>