octeontx2-af: Enable hardware timestamping for VFs

Currently for VFs, mailbox returns ENODEV error when hardware timestamping
enable is requested. This patch fixes this issue. Modified this patch to
return EPERM error for the PF/VFs which are not attached to CGX/RPM.

Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Sai Krishna <saikrishnag@marvell.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20231011121551.1205211-1-saikrishnag@marvell.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>