MLK-18675-04 brcmfmac: return -EPERM when getting error in vendor command handler

MLK-18675-04 brcmfmac: return -EPERM when getting error in vendor command handler

Firmware returns proprietary error code when getting error in
fil_cmd_data_set or fil_cmd_data_get. Sometimes the vendor tool or
utilities which uses libnl may stuck in some commands when wl is down.
For example, issue "scan" command after issuing "down" command, the
"scan" command will be the blocking call and stuck as no response from
firmware. It is caused by that firmware returns BCME_NOTUP(-4) when wl
is down, but in Linux the -4 is -EINTR, so libnl catches the error and
not pass to upper layer.
Because of that, the driver should return Linux error code instead of the
proprietary error code, and the tools or utilities need to get the real
firmware error code by another command "bcmerrorstr" after receiving
the error.

Signed-off-by: Wright Feng <wright.feng@cypress.com>
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Vipul Kumar <vipul_kumar@mentor.com>