qrtr: Rename qrtr_all_nodes to qrtr_all_epts

The node list only respresents the adjacent nodes in the system. Rename
the list to qrtr_all_epts to better describe the list contents.

Change-Id: I168ca597d5b9b30d6c064c2a56b6e8b2dffa387b
Signed-off-by: Chris Lew <clew@codeaurora.org>