[ena] Provide a host information page

[ena] Provide a host information page

Some versions of the ENA firmware (observed on a c6i.large instance in
eu-west-2) seem to require a host information page, without which the
CREATE_CQ command will fail with ENA_ADMIN_UNKNOWN_ERROR.

These firmware versions also seem to require us to claim that we are a
Linux kernel with a specific driver major version number.  This
appears to be a firmware bug, as revealed by Linux kernel commit
1a63443af ("net/amazon: Ensure that driver version is aligned to the
linux kernel"): this commit changed the value of the driver version
number field to be the Linux kernel version, and was hastily reverted
in commit 92040c6da ("net: ena: fix broken interface between ENA
driver and FW") which clarified that the version number field does
actually have some undocumented significance to some versions of the
firmware.

Fix by providing a host information page via the SET_FEATURE command,
incorporating the apparently necessary lies about our identity.

Signed-off-by: Michael Brown <mcb30@ipxe.org>