brcmsmac: add support for cores with revision 17

This adds support for bcma wifi core revision 17 which is found on
BCM4716/4717/4718 SoCs. The firmware version 610.812 for brcmsmac found
in linux-firmware does not support these cores, but a firmware
generated with b43-fwcutter from the proprietary broadcom wireless
driver works with these chips. This wifi core contains a revision 5
N-PHY and a revision 7 radio of type 0x2056.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>