brcmfmac: add BCM4334 support

BCM4334 is a dualband a/b/g/n WiFi chip support 20MHz/40MHz
channels. This patch adds support for its SDIO interface.

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