Move SensorSubTree declaration to ipmi scope

Move SensorSubTree declaration to ipmi scope
Issue: Unable to resolve this symbol during loading of this
library, which is due to definition & declaration being in different
scope.

Unit-Test:
Verified that library is loaded properly and ipmitool sensor list
works.

Change-Id: I243e0033d0b76a14c0976f16bd6b893c0e96cb55
Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
1 file changed