IB/cm: Endianness annotations

Mostly update the RB tree comparisons to force __be types to normal
integers, but the change to cm_format_sidr_req() is a real fix:
param->path->pkey is already __be16.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
Acked-by: Sean Hefty <sean.hefty@intel.com>