wilc1000: use API version number info along with firmware filename

Added version number info along with firmware name so driver can pick
the correct revision of FW file. Moved FW filename macro as part of
driver code & added MODULE_FIRMWARE to specify FW needed by module.

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200710051826.3267-6-ajay.kathat@microchip.com