staging: wfx: remove unused definition

The enum hif_fw_type is never used in the driver. Drop it.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20210913130203.1903622-22-Jerome.Pouiller@silabs.com


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