brcmfmac: add support for dongle ARM CR4 core

Newer WiFi chip use ARM CR4 core to achieve higher performance. Add necessary
code for host driver in order to support CR4 core.

Reviewed-by: Arend van Spriel <arend@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Franky Lin <frankyl@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>