pcie: Remove odata.context

Redfish made odata.context optional (1.6.0 of DSP0266) and
has removed odata.context from example payloads in the
specification (1.7.0 of DSP0266), removed it from the mockups,
and Redfish recommended not using.

Change-Id: I262f21aac32634f8e87863cca7816e4b9236227a
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>