staging: brcm80211: renamed ioctl functions/structs to dcmd

The fullmac dongle communicates with the driver using certain codes. These
codes were named 'ioctls' in the code, but this term is confusing since
it is used in kernel<->driver context. The term 'ioctl' has been replaced
with 'dcmd' for 'dongle command'.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Arend van Spriel <arend@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Signed-off-by: Franky Lin <frankyl@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>