[Hexagon] Enable .cur formation in MISched for Hexagon V60

Schedule a load and its use in the same packet in MISched. Previously,
isResourceAvailable was returning false for dependences in the same
packet, which prevented MISched from packetizing a load and its use in
the same packet for v60.

Patch by Ikhlas Ajbar.

llvm-svn: 275804