fpga: dfl: drop unneeded get_device() and put_device() of feature device

fpga: dfl: drop unneeded get_device() and put_device() of feature device

The feature device data was originally stored as platform data, hence
the memory allocation was tied to the lifetime of the feature device.
Now that the feature device data is tied to the lifetime of the DFL PCIe
FPGA device instead, get_device() and put_device() are no longer needed.

Signed-off-by: Peter Colberg <peter.colberg@intel.com>
Reviewed-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Reviewed-by: Basheer Ahmed Muddebihal <basheer.ahmed.muddebihal@linux.intel.com>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20241120011035.230574-18-peter.colberg@intel.com
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>