nitro_enclaves: Set Bus Master for the NE PCI device

Enable Bus Master for the NE PCI device, according to the PCI spec
for submitting memory or I/O requests:

 Master Enable – Controls the ability of a PCI Express
  Endpoint to issue Memory and I/O Read/Write Requests, and
  the ability of a Root or Switch Port to forward Memory and
  I/O Read/Write Requests in the Upstream direction

Cc: Andra Paraschiv <andraprs@amazon.com>
Cc: Alexandru Vasile <lexnv@amazon.com>
Cc: Alexandru Ciobotaru <alcioa@amazon.com>
Reviewed-by: Andra Paraschiv <andraprs@amazon.com>
Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Link: https://lore.kernel.org/r/20210621004046.1419-1-longpeng2@huawei.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>