brcmfmac: separate firmware errors from i/o errors

When using the firmware api it can fail simply because firmware does
not like the request or it fails due to issues in the host interface.
Currently, there is only a single error code which is confusing. So
adding a parameter to pass the firmware error separately and in case
of a firmware error always return -EBADE to user-space.

Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>